[Kellermann, September 2008]
Kellermann, September 2008. NRAO/AUI image



[Kellermann and Reber, spring 1995]
Kellerman and Reber, spring 1995. Image courtesy of Ken Kellermann



[Kellermann, January 1970]
Kellermann, January 1970. NRAO/AUI image



[VLBA telescope map]
VLBA telescope map. NRAO/AUI image



[Ken Kellermann, early 1960s]
Kellermann at CalTech, early 1960s. Image courtesy of Ken Kellermann



[Kellermann, July 1977]
Kellermann, July 1977. Image courtesy of Marshal H. Cohen



[Map of early VLBI locations]
Telescope locations and baselines for early VLBI experiments. NRAO/AUI image


NATIONAL RADIO ASTRONOMY OBSERVATORY ARCHIVES

Papers of Kenneth I. Kellermann: Oral Interview Series

Interview with Thomas A.Matthews
At Matthews' home
April 28, 2012
Interview Time: 1 hour, 8 minutes
Transcribed by Sierra Smith

Kellermann

Iím here with Tom Matthew at his home and itís April 28th [2012].

Matthews

Thatís correct.

Kellermann

Tom, were you aware that John Bolton back in 1960 claimed that he measured the red shift of 3C48 as 0.37?

Matthews

Well, yes. That and, ok, let me go back and start.

Kellermann

Yes, please.

Matthews

The Owens Valley Radio Observatory was constructed- I mean, I had a part in laying it out, a very important part in laying it out quite frankly. I set up the North-South and East-West baselines accurately and in the process figure out that the Wild T3 [theodolite] that we were using as a survey instrument had bearing errors.

Kellermann

Oh, I didnít know about that.

Matthews

Well, I was making direct and reverse measurements and getting results that didnít work. And so I said, "Look, there must be something like that." So I set up a little experiment in the sub-sub-basement at Caltech, a long string on a weight and a can of water and got off far enough so I could measure the thing with the Wild T3. And I found the error that I expected to find between the direct and reverse measurements because I was measuring the pole star and then dropping down to the height of the north or the 90į away for the east. But setting north first was the first problem. But anyway, so the directions of the whole system of the tracks was good, my measurements were good to about 1 second of arc or so and it took awhile to get there. And then the dishes were built. And we started observations with the closer separation to begin with and that gave us good Right Ascensions- it was the east-west interferometer first- good right ascensions to 1/10th second of time, quite frankly.

Kellermann

So that is a few seconds of arc?

Matthews

Yeah, or actually, we could easily do a 1/10th second of time. And then Al [Alan T.] Moffet started making observations at the wider and wider east-west separations all the way out to 1500 feet, getting diameter data. Ok, he got all that and then we went to the IAU [International Astronomical Union] Meeting in Berkeley. And there Al Moffet met the Jodrell Bank group- I donít remember the guyís name who...

Kellermann

Henry Palmer.

Matthews

Yes, Palmer. Youíre quite right. And got a preprint of their results, which I made a copy of, and so I had that material to work with as far as diameters were concerned. I had our measurements for right ascensions, which were certainly as good. I had the 3CR catalog, which came out of Cambridge. And I donít remember the guyís name who was doing the 3CR but he set up a complete array to measure both right ascension and dec [declination] and they were by far the best position measurements that Cambridge had and the 3CR was about as clean as any list could be.

Kellermann

3CR came later.

Matthews

Yes, but was there. It was already out, just out.

Kellermann

That was the original 3C?

Matthews

Well, the 3C had lobe shifts in it. The 3CR got rid of all side lobes. I actually found one or two lobe shifts still there but it was very rare, and certainly those declinations were better than anything else that we had at that point. So those were the position measurements. And then I was doing the identifications, so I had access to the survey plates actually, which you can no longer use this way. And I looked at the original plates and had to find where the Right Ascensions were to, you know, they were on the order of a second of arc. Well, the plates were centered on stars when possible, which were in what are known as the CD catalog of astrometric star positions. Itís a great, big, thick catalog, which is a sum total of all the astrometric information from all the observatories north and south, in Europe, and South Africa, and U.S., and so on. And that was all put together and itís a standard reference. So that is where I started. I could identify their stars down from 5th to about 9th magnitude essentially. I identified those on the plates and quite often the plates were actually centered on one of those stars and the guide star was one of those stars quite frankly.

Kellermann

You mean the 48 inch plates?

Matthews

Yes. So per plate, there were usually several such stars on the plate. I picked the nearest one to the source and offset our positions, which referred to the identified radio sources, the relativity few that were known accurately. And so that fixed our system. And then I offset on three times enlargements on the Xerox machine- silly way but it worked- and got to, well, to positions that I felt were good to at least a couple of seconds of arc, if not better. So then I pinpointed the objects and normally, as long as they were out of the galactic plane, I could usually identify them immediately. It was very simple even though many of them were double.

Kellermann

The radio sources.

Matthews

The radio sources are double. For some reason- well, I guess we know why- the position of the object is midway between the two components. One would expect a little bit of offset but maybe not. But anyway, it turned out there wasnít. So that had gone on and I was able to identify quite easily most of the objects as long as they werenít in the plane. So I said, "Alright, let me see if we canít do a little bit better." Cygnus A had been identified by [Walter] Baade and [Rudolph] Minkowski as a pair of colliding galaxies, pretty distant, and it was the highest red shift at the time. And I said, "Well, letís see if we canít better that." How to do it? Well, my first thought was letís try for small diameter stuff. And so thatís what I did, from Al Moffet and the Jodrell Bank work, was to pick things that were not resolved at the largest baselines. And I went to the 3CR and I went down in order of radio brightness and I said, "Letís get the brightest non-identified radio sources that had small radio diameters." And that was the origin of my list, CTC list. And I donít remember exactly how many sources were on it but it was 15-20 of that order anyway.

Kellermann

The CTC list had several hundred.

Matthews

Well, ok, this was a subset. Ok, thatís why I asked you the question over the telephone to make sure that we were or were not talking- Iím talking about a separate list. I made a list of probable what I thought were high red shift objects that had been totally unidentified and I shared this list with Martin Schmidt. And I donít think I shared it with anybody else quite frankly. And then having the best possible positions and looking at the objects on the survey plates, I said, alright, the first one I looked at was 3C48 and it was easy. Schmidt pinpointed this star-like object and I couldnít tell anything more than that about it.

Kellermann

So, on this Schmidt plate you couldnít see the jet?

Matthews

No, you could not see anything else. I asked Alan Sandage to get me a 200 inch photograph of it, giving him a finding chart, which he did and handed it to me. And I looked at it very carefully. It was a blue plate and I could see the object and on that plate, which was a pretty deep plate, I could see faint nebulosity. I had no idea what the nebulosity was. It could have been gas around a star. The image certainly was star-like in every way I could tell but I knew it was not star because of that extra very faint and off set, not centered but slightly off set...

Kellermann

Was the radio position good enough to distinguish between the identification with the nebulosity and the star?

Matthews

No, it pinpointed the star though.

Kellermann

It did?

Matthews

Yeah.

Kellermann

Ok.

Matthews

No question at all. It fell right smack dab on top of it. So there was no question there. I told Alan Sandage that. I think he got- no, he did not and he didnít get the first spectrum of it. I think that Jesse Greenstein got the first spectrum but everybody jumped on the bandwagon.

Kellermann

So you showed Jesse the image?

Matthews

Yeah, I mean I saw him a lot.

Kellermann

But he got it from you?

Matthews

Yes, oh yes. And well, Guido Munch got observations. Al Baum got observations of the photometry. Alan Sandage did photometry on it.

Kellermann

He found it was variable.

Matthews

He found that there was ultraviolet access and that it was variable on the time scale of at least a week, if not smaller. But that also showed up when- whatís his name, Smith...

Kellermann

Harlan Smith.

Matthews

Harlan Smith looked at the Harvard survey stack of photographs of the sky going back many years and found indeed that there was variability in it. So that was the, I think, confirmation at least of Alan Sandageís finding. And that, of course, everybody got in on the act but the spectrum showed these strong pair of emission lines that nobody could identify. And we did considered red shifts but not big enough red shifts. And so it stayed that way for about three years. During that three years, I identified two more, 3C286 and 3C296 [Kellermann: should be 3C196]. Again, 286 showed- Alan Sandage took plates of those too- and there was the nebulosity, quite asymmetric in 3C286. So I said, "Well, they look like a pattern." And so, we sort of put together that paper which was talking about the identification of quasi-stellar radio sources. Now, the first publication, if you can call it that, the identification of 3C48 took place in mid-December of 1960 and Alan Sandage was at the AAS meeting- I guess was in Boston or New York, I donít remember...

Kellermann

But I do remember it was the AAS meeting, right.

Matthews

And we sent him a telegram saying weíd identified it.

Kellermann

We being?

Matthews

Well, Bolton, everybody got in on the act. John Bolton got his name on it. Jesse Greenstein got his name on it. I donít know who else got his name on it. Itís all in there in the Nature...

Kellermann

Well, Sandage because he...

Matthews

Well, Sandage very definitely. No, he was very important. And so Alan Sandage announced it at that meeting.

Kellermann

So Alan did not know about the ID until you had sent him the telegram.

Matthews

Thatís exactly right.

Kellermann

That I didnít know.

Matthews

And, of course, Sky & Telescope published it on the inside cover of that monthís or next monthís...

Kellermann

And that was the only publication, yes.

Matthews

Thatís exactly right. Thatís the only publication. They ripped out all the ads and used the space. Well, I happened to know the editor at that point, who is a friend of mine, because I had met at [?].

Kellermann

Is that Leif Robertson or was that later?

Matthews

No, that was beforehand. His name escapes me but anyway...

Kellermann

So you sent it to Sky & Telescope?

Matthews

I didnít send it, no.

Kellermann

He picked it up at that meeting?

Matthews

He picked it up at the AAS meeting.

Kellermann

Did he talk to you about it at all?

Matthews

No, he didnít. Well, all the information was given to Alan Sandage and he gave it at the meeting. We didnít have anything else. We knew what the spectrum was. It was not normal and we didnít understand what it was. And we didnít understand any of them that we got for the first three years because we didnít consider high enough red shifts.

Kellermann

Well, let me show you and Iíll leave this with you, this is a copy of a letter John Bolton wrote just before he left Caltech. This is November of 1960 and he mentions lines of Neon V and Argon III and IV and it has a red shift of 0.367.

Matthews

Iíve never seen that before.

Kellermann

I know you havenít. Nobody has seen it.

Matthews

Thatís interesting.

Kellermann

It was a letter to Joe [Joseph L.] Pawsey and this was found in Pawseyís papers in Australia. But a few weeks later, he writes again that this is wrong and itís a star, a Galactic star. He got talked out of it.

Matthews

By who?

Kellermann

Apparently either Jesse or Ike Bowen because the wavelengths of the different lines...

Matthews

My guess is that it was Jesse.

Kellermann

Yeah, the wavelengths did not line up quite right and we now know itís just the velocity dispersion but that wasnít accepted at the time nor was, and he says here that, "The absolute photographic magnitude is then -24, which is two magnitudes greater than anything known."

Matthews

I donít understand. That doesnít make sense, does it?

Kellermann

Well, it was a Hubble constant of 100, so yeah.

Matthews

That was pre-understanding.

Kellermann

Yes, of course.

Matthews

And thatís interesting that he wrote that though.

Kellermann

Yeah, Iíll leave that with you. You can have it.

Matthews

Thank you. Now, I mean what happened-I donít even remember the Australianís name who did the occultation of 3C273...

Kellermann

Hazard.

Matthews

Hazard.

Kellermann

But John Bolton never mentioned that to you?

Matthews

Never, never. John Bolton actually invited me to join him in Australia. I thought carefully about it but I had three young children at that point and all my family was either in Canada or Annís family was in Nashville and well, her elder sister was out in Manhattan Beach, California...

Kellermann

Well, I did go for two years when I finished at Caltech.

Matthews

I see. Good for you.

Kellermann

No, that was good.

Matthews

So I thought about it very carefully but decided no, it would probably not be a good idea for me. And thanked him but said no. Maybe I should have. Well anyway, Hazard was in communication and sent his observational results on 3C273 to Martin Schmidt directly. I knew nothing about it. 3C273 was not on my list because it was a larger source. I had selected against those larger sources. And the interesting thing is that my selection selected out all of the doubles. Presumably- and this is thinking about it later- what I had selected could well be quasars that were actually pointed at us, the beam was pointed at us, and therefore very small diameter.

Kellermann

Sure, but Hazard only sent Schmidt the position. Who made the identification?

Matthews

Martin.

Kellermann

He doesnít think he did.

Matthews

Well, no, Iím sorry.

Kellermann

He thinks he got the id from somebody, maybe you.

Matthews

No, he did not. I knew nothing about it. I think Hazard must have sent him the identification because I did not. And Martin went up to Palomar [Observatory], got the spectrum, developed it, saw the hydrogen line sequence, and immediately knew that he could measure the red shift, which he did actually, and came down and told us. Well, fifteen minutes later, Jesse and I knew what the red shift of 3C48 was. And it was that quick and we just hadnít thought about high enough red shifts period.

Kellermann

Martin said that he first overexposed it because you donít use a 200 inch telescope for.

Matthews

Bright star. Youíre quite right. I didnít know that.

Kellermann

Yeah, but I think he also puzzled over it for a few weeks. I donít think he recognized the spectrum right away.

Matthews

That was not what he told me.

Kellermann

Really? So you say as soon as he came back?

Matthews

He actually measured it when he was up there.

Kellermann

Measured it and understood that...

Matthews

Knew it was the hydrogen sequence. I donít know whether it was- I think beta was already in the infrared so it would be H gamma and so on and knew what the red shift was. And he came down and came in, you know, at 9 oíclock, whenever he got it, and he told us and he said, "Look, this is the identification and this is the red shift." And then, we went- well, at least Jesse went and very quickly did the appropriate calculations. And when we search for a match for the emission lines- Martin could see the emission lines on 3C273. So, I mean, that gave us the identification and so everything was straighten out at that point. But that was three years after we discovered the damn things. Well, thatís my remembrance.

Kellermann

Minkowski was apparently in Australia at the same time. Do you know about that?

Matthews

No.

Kellermann

So he apparently had some finding chart.

Matthews

He may have identified it.

Kellermann

Well, thatís what I was wondering.

Matthews

Thatís certainly a possibility. In fact, I would not be surprised if Minkowski had.

Kellermann

Because Hazard said he had no experience doing that...

Matthews

It must have been Minkowski then.

Kellermann

And Hazard says that he got the position and he had no experience looking at the plates or prints or anything or how to align them up.

Matthews

Well, because Martin did have a chart, a finding chart of it, and he knew where to look.

Kellermann

Yes, he says that, right, but he doesnít recall where he got...

Matthews

And my guess is that it was Minkowski then. That would make all sorts of sense to me. I did not know of his doing it though. I knew Minkowski quite well. I knew Walter Baade maybe a little bit better probably. Baade was a fascinating person. He was really a raconteur.

Kellermann

I think he had died by the time I had got there. I got to know Minkowski a little bit because he was still around when I came.

Matthews

Yeah. Well, anyway, I went on to identify continuing objects on my list. 3C171 was one of my real outstanding- I remember it so well because 3C171 was in the Galactic plane. And so you look at this thing, itís in the anti-center region and you see the survey plates, 48 inch plates, are rife with stars. Thank goodness, they werenít as bad as the center. You couldnít possibly identify anything in the direction of the center, too many stars. But anyway, I didnít know if my line of sight could get through the interstellar dust to see anything out beyond it. But when I got the position, it was a small triangle- literally three almost identical star-like objects within about a couple of seconds of arc of each other in a little triangle, two at the lower Right Ascensions and then a third to slightly higher Right Ascension but within seconds of arc. And I said, "Itís got to be one of those,"...

[Small break in interview due to a telephone call]

Kellermann

We were talking about 3C171.

Matthews

3C171. Well anyway, the position suggested that it was one of the lower Right Ascension objects and I couldnít tell from the declination which one it was and so I gave this information to Martin Schmidt. I gave him a finding chart and he put both objects on the slit of the spectrograph and took two spectra at the same time. And it was the lower one, just as I had suggested it might be. And that was the highest red shift for awhile anyway.

Kellermann

It was happening very fast. Thatís right.

Matthews

But anyway, I was amazed that I could indeed see through, there must have been very little absorption between us and 3C171. There was another source that I saw also in the Galactic plane in the anti-center region, which was a galaxy that actually poked its nose through a hole too, and was identified. But, I mean, nothing special about it, just an ordinary galaxy- not an ordinary galaxy, no.

Kellermann

Yeah, none of them were ordinary, of course.

Matthews

Well, a little bit abnormal.

Kellermann

But back on 3C273, so you said it wasnít on your list because it wasnít small but there were a number of other sources that you worked on that werenít so small. They are identified with radio galaxies and you wrote the paper and everything on it, double sources and...

Matthews

Well, ok. I had made a number of identifications and I kept coming up with odd shapes which looked like elliptical galaxies but some of them were in clusters and they were obviously the brightest object in the cluster. Looking at the literature, I noticed that Bill Morgan from Yerkes was talking about something he called D galaxies. When he came to visit and I pin-holed him and said, "What in heavenís name are these D galaxies that you are talking about?" And we had a discussion. I said, "Iím finding my identifications look as if theyíre that kind of object." So I showed him a couple and he agreed. He said, "No, these are not what I thought," because the D objects that he was talking about were actually some of the more spiral, notably spirals, but had rather large, bright central regions. So we sort of refined that identifications and started calling them cD.

Kellermann

Yes, I remember that.

Matthews

Well, the c turns out to be a spectroscopic designation for super giant. Bill Morgan used this in his catalog of spectra. So we were using that designation to talk about super giant elliptical galaxies. Thatís where that term came from.

Kellermann

I see. But it originally referred to super giant stars?

Matthews

No, no.

Kellermann

Super giant galaxies.

Matthews

I knew these were galaxies because they were definitely elliptical-like galaxies but were abnormally bright and abnormally big. And that was what we pointed out in that paper, Matthews, Morgan, and Schmidt.

Kellermann

Right. But many of those radio galaxies had, you know, reasonable size, they were doubles, so I still wonder why 3C273 wasnít identified much earlier? It was a strong source, 13th magnitude counterpart, how could you..?

Matthews

I never got around to looking in that part of the sky is the point.

Kellermann

Is that because it is the same right ascension as M87?

Matthews

No.

Kellermann

I mean it is the anti-center, itís the best part of the sky for...

Matthews

I totally agree with you. It was essentially the fact that my attention had not got around- as I remember the right ascension of 3C273 is somewhere around 12 hours, and for some reason, our observations for position measurements really had not got into 12 hours.

Kellermann

Is that because you did it at a time of the year when 12 hours is near the sun?

Matthews

Yes, entirely and, so therefore, I hadnít really focused on it and Hazard beat me to it. I think if I had ever started to look I would have found it very quick.

Kellermann

Yeah, I would have thought so.

Matthews

I just never looked for it and the only reason is because we werenít observing in those particular right ascensions, the wrong time of the day.

Kellermann

But in the three years, I mean you started...

Matthews

Ok, itís happenstance. I canít explain it at all.

Kellermann

I had asked that question to John Bolton. John claimed it was because it was the same Right Ascension as Virgo A, which was a standard calibrator.

Matthews

No, we werenít using it as a calibrator because once we calibrated the Right Ascension and so on. It all depended on where you sat the antennas down and if you did it right, you were locked into our well-defined north-south and east-west tracks.

Kellermann

Dick Readís thesis had a good declination some years earlier.

Matthews

Oh, yes. Well, that was later though. Well, I donít know.

Kellermann

I graduated in í63. Dick graduated in í62 and that work was done earlier.

Matthews

His thesis was on the declination?

Kellermann

Thatís right and he had it within 6 seconds of arc or so which should have been enough to identify...

Matthews

Easily, easily. But I just never looked. Thatís all I can say, I never looked.

Kellermann

Right.

Matthews

And, ok. The list that I had and this list as I say was somewhere around 15, probably a little more than 15 objects, and Martin Schmidt actually refers to that list in an IAU meeting volume. And I guess itís on quasars and I donít remember the date for it but I found it. And he actually talks about that list that I had given him and said that, "Every one of the objects on that list turned out to be a quasar, every one." I mean thatís phenomenal.

Kellermann

Ok, Iíll have to look that up. Do you remember about when that meeting was?

Matthews

No.

Kellermann

Or where?

Matthews

It was in New York somewhere and I donít know the answer.

Kellermann

I think I may have been there. I donít remember that specific meeting. It was an IAU Symposium?

Matthews

Itís in there in publication.

Kellermann

Yeah, an IAU symposium.

Matthews

And as I remember, it was on quasars.

Kellermann

Yeah, I think I remember the meeting too. It was a tenth anniversary or something.

Matthews

And so anyway, I mean putting it all together now, it really makes sense to me to say that list happens to be quasars, if one can use that term in that sense, that are pointed directly at us. They must be.

Kellermann

Yes, with our current understanding.

Matthews

Yeah. Well anyway, the other thing that I guess was interesting- well, that essentially- let me finish the topic first. I went on to identify a few more in that list. I did not identify all of them. My appointment was not renewed and I guess I can give you the reason for that. I was invited to give a talk at the first, I guess it was the first, Texas Conference on Relativistic Astronomy...

Kellermann

Astrophysics. Relativistic Astrophysics, yeah.

Matthews

Yeah, thatís right. And I had been considering the problem and was working on trying to synthesize what in the hell we were finding. And just prior to that, I guess one of the things that had triggered my interest was a prepublication from our group- I donít remember, it was Morris and somebody I think- talking about polarization of radio sources.

Kellermann

It would be Morris, yeah.

Matthews

And, thatís the first Iíd heard of it and I said, "My, thatís an interesting thing." And I was also thinking at the time about Cygnus A, high resolution observations. I guess it was from Jodrell Bank.

Kellermann

Cambridge I think.

Matthews

Iím sorry.

Kellermann

I think it was Cambridge.

Matthews

Yeah, was it Cambridge who was showing the brightness on the outer edge?

Kellermann

It was Cambridge.

Matthews

I didnít remember that. In any case, it seemed to me that that was significant and I was trying put together some sort of scenario that would meld this all together. And Iíd been working on it, thinking about it and working on it. So my thought was that you had these jets coming out from the accretion disk essentially around a black hole. We knew there were black holes at that point. It couldnít be anything else. And you have the very high temperatures and very high magnetic fields in the inner edge and in some manner that focused the jets perpendicular to the accretion disk. And well, I guess it was probably some of your work on the low mass black hole, was it Cygnus X...

Kellermann

Cygnus X3. No, I didnít do anything with that.

Matthews

You didnít do that? Well anyway, somebody did. I donít remember who it was. And the accretion disk tilted and was not exactly the same as the rotation of the objects. And so you got this corkscrew thing. Well, that sort of explains a lot. But in the case of a super massive black hole, you certainly donít have the super massive black hole precessing, much too much mass involved. But the much lower mass of the accretion disk could have a slow precession, if you want to call it that, involved. It would be a much slower time scale, one I havenít any clue what. I was listening to a very interesting NOVA program, as a matter of fact, just about a week ago on quasars, blasars actually. And there was a comment there that, well they were talking about quasars and blasars both, and they said that it looked as if the accretion disk probably didnít add any more than about 20 solar masses per year in it and it was one of the most efficient energy conversion mechanisms that exists, from gravitational energy into relativistic protons and electrons. And I would believe that but it sounds to me that could be a theoretical result. I donít think we have any observations on that one. Although, you might almost get some if it is the right observations- thatís speculation.

Kellermann

Yeah, I really havenít followed that work well.

Matthews

Well, I think itís important because one needs to know more about how those jets get formed. Theyíre certainly incredibly focused.

Kellermann

I think that there has been, well, obviously a lot of X-ray work done. Thatís what Cyg X is.

Matthews

Well, but, I mean, one has to worry about the confinement. I suggested that it may well be- when I gave this 20 minute speech in that Dallas Conference, I suggested that we might have magnetic confinement involved and that looking at Cygnus A hot spots, it looks as if there is an impingement on this jet on some medium which reacted to magnetic fields. And that is what caused the brightness of the edge, the outer edge, of Cygnus A and probably one had a randomization of velocities of the particles at that point. And I couldnít say anymore than that. But what I did do was make some calculations using hydrodynamic equations and saying, "Ok, you have to have about a factor of 4 density difference inside to outside which implies that there has got to be material there, matter there, which it is impinging on that is responsive or interacts with a magnetic field. Itís not dark matter." And the thing is after I gave my speech and was walking back to my seat, I saw Fred Whipple from Harvard who is a theorist among other things- was a theorist, sorry, heís dead now. And he commented to me on my way by that, "You realize that you are implying that there is matter out there that we know nothing about." And heís right, entirely right, and in fact, I know of no other confirming evidence to say that because this is normal matter. As far as I am aware there are no suggestions that dark matter interacts with a magnetic field, I donít think. I donít know if that comment is right but Iíve not heard anything like that. And so if you look at the highly detailed maps that came out of the VLA of some of the closer galaxies which had spread sources with a highly detailed density or intensity or the radio structure and so on showing hot spots, hotter spots anyway, fairly close to the galaxy but then all this rather large, amorphous lobes outside. It seems to me that somehow that energy has been transformed from a highly organized jet into a more diffuse expansion to produce those lobes and thatís the more relaxed stage, the final stage. But I know of nobody whoís actually studied that in the sense of getting polarized maps to show something where the magnetic fields are.

Kellermann

Yeah, I think people are doing that now with the VLA. You can get fairly detailed...

Matthews

Thatís what you need. And there should be some indications of expansion, slow expansion, which is probably slowed down significantly. I mean, you got the hot spots in 3C278 for instance- NGC 5128, excuse me, and then the much larger lobes. The hot spots, I mean those jets, must go on for a significant length of time as long as the accretion disk is being fed, which means probably for some millions of years.

Kellermann

At least, yeah.

Matthews

After a collision or something, maybe billions of years, quite frankly. But eventually somehow itís got to end up being a much slower, more relaxed expansion to produce the lobes. And the question is, how does that happen. Itís a very complex magneto hydrodynamics problem but nobodyís studied it.

Kellermann

Well, like you say, itís complex. I certainly couldnít begin...

Matthews

I canít handle it. But it seems to me that if one studied such objects as the small objects in Cygnus A and other such objects and the jets in maybe M87, NGC 5128, and where ever they exists, where you have a hope of getting high detailed observations of them that you might understand a little more about the confinement. There is by the way, there is a guy at [NASA] Goddard [Space Flight Center] here who about ten years to thirteen years ago came out with a theoretical model of what the geometry of the magnetic field would look like. And itís a spiral, slow spiral which is doing the confining, and gives you if you average over it, gives you this longitudinal average, which gives you the polarization that we see.

Kellermann

Yeah, I think there are lots of models.

Matthews

I think there are a number of people who have done that. Thatís one, nice diagram that I happen to come across looking at the Hubble results. But, I mean, thatís got to be the jet, thatís one aspect of it, how it interacts with the medium, maybe from Cygnus A or other objects like that, again high resolution radio observations.

Kellermann

There has been a lot of work recently on the interaction between the very small scale jets and the intergalactic medium in the so called feedback, how the small relativistic jet influences star formation in the galaxy and how the interstellar medium of the galaxy impacts the formation of the jet.

Matthews

But we are talking in Cygnus A, for instance, those components are well outside the galaxy and so it still interacting with something, something that responds to a magnetic field.

Kellermann

Yeah, I said interstellar. I should have said intergalactic.

Matthews

And the problem is what to we know about normal matter that is intergalactic? And we donít know a hell of a lot because you canít observe it very well.

Kellermann

Well, other than through its interaction with the radio source, the relativistic plasma giving rise to the radio emission.

Matthews

For instance, when you are looking at these lobes, there must be a balance between the expansion of the lobe and the gravitational force of the dark matter, as well as the normal matter holding it in. I mean, we know some of the details about the dark matter around our galaxy. We know that itís slightly flatten, we know that it is somewhat clumpy, as a matter of fact. There is a very nice article by Leo Blitz on that. And well, thatís that most detailed information I know of about what dark matter around galaxies are like and thatís got to be balancing the expansion of the radio source lobes. And so itís got to be a pressure balance, in some sense. And this is why I say youíve got to look at the polarized maps of those lobes and see whether you can see expansion, for instance.

Kellermann

Yeah, thatís coming out of the VLA. Anyway, you started to talk about your leaving Caltech.

Matthews

Yeah, well anyway, after I gave my talk, I got back to Caltech and Gordon Stanley came in and he just gave me hell. He said, "You plagiarized the material," about this polarization of radio lobes. And I said- well I didnít say it, I should have, I didnít, "Look, itís been pre-published and thatís where I got the idea." And I had not written my article out. It was still in a formative stage. I felt I needed to at least be able to respond to comments like Fred Whippleís...

Kellermann

When you say pre-published, you mean it was in the Caltech Yellow Jacket?

Matthews

Yeah, exactly. I donít know that I ever saw the published results. It may or may not have been published. But anyway, it was circulated and I wasnít stealing anything. I hadnít written my article but the negativity that I received from him, I mean, it wasnít long after that I was told that my contract wouldnít be renewed.

Kellermann

I also had my problems with Gordon. He was in over his head.

Matthews

He didnít know what the hell he was doing. He knew the electronics superbly but he didnít understand the physics of it, the astronomy of it.

Kellermann

He also didnít understand people.

Matthews

Thatís true too. Thatís very true.

Kellermann

So, I had some very difficult times with him. In the end, decades later, we sort of smoothed it over and everything. You know, it was long in the past. But he...

Matthews

I never got along with him.

Kellermann

Many of us didnít. He really didnít know how to proceed.

Matthews

He really didnít. He was totally clueless.

Kellermann

And itís my impression at the time Caltech was not particularly interested in building up a permanent staff in radio astronomy.

Matthews

Well, there wasnít anybody else really to do it at that time.

Kellermann

Thatís right but no, I mean, people like you or me, not director, but even stay on there.

Matthews

I agree with you. I think thatís true. Well anyway, I never wrote that article. I should have written the article. I had to have done more work on it quite frankly because I only had bits and pieces of it and I had not written anything concrete down- well, I had, enough to give the lecture anyway, the talk.

Kellermann

Yeah, thatís easier than writing it up. It always is.

Matthews

But it was very much preliminary and I was just totally disheartened by the response because I never got any positive response to it, period, from anybody.

Kellermann

So you were saying when I first came in and I havenít seen that article about Alan Sandage, you say it gave him more credit than he should have...

Matthews

Well, the whole point that Alan Sandage was responding to my request. I mean, I said, "Hereís the identification. Could you get me a picture of it?" And I did this several times with Alan, for the first three anyway, and then after that I had confidence in my technique so that I that I didnít really need to do much more than say, "Look," to Maarten Schmidt. I said, "Hereís the identification from the survey plates of this object. Would you like to take a spectrum of it?" And I was looking on one with Martin Schmidt at that point and my interaction with Alan- we didnít go to zero, we wrote a paper together on the first three anyway but without knowing what the red shifts were.

Kellermann

I can tell you and I have it in writing and I will send it to you, Alan on several occasions emphasized to me your role and that it wasnít fully recognized. He certainly was not trying to take any credit.

Matthews

No, no, no. I donít accuse him of that.

Kellermann

I know that. I just wanted you to know how strongly he felt.

Matthews

Well, he told me that himself and I got it actually from one or two other people.

Kellermann

He said you were the key to the whole thing.

Matthews

Well, thatís true. Thatís true. There is no question in mind that I made those identifications and I relied on him to get 200 inch time and get better photographs, deeper photographs, which was what we needed. And then, of course, once they were identified we had to get spectra and there was no other instrument that could get the spectrum either. I was not allowed to get time on the 200 inch so I had to work with somebody who did.

Kellermann

But ironically as things happened most of the publicity came as a result of the 3C273, not the 3C48...

Matthews

But that was three years later.

Kellermann

That was three years later but thatís what people remember now.

Matthews

Thatís right and thatís what needs to be corrected, I guess. Youíre writing a book on the subject, arenít you?

Kellermann

No, certainly not writing a book. I am giving a talk this summer at the IAU. There is a session on discoveries in astronomy and I am giving a talk on quasars.

Matthews

Good. Well, ok, you know the answer then.

Kellermann

And well, itís like your earlier thing, there will be an option to write that up so Iíll try to do that.

Matthews

Good, good. Do you have any other questions?

Kellermann

No, thatís it. Itís been very interesting. So, I asked you, you donít have a copy of that CTC list or your smaller list?

Matthews

I gave my last copy to Larry Kraus. He probably doesnít remember anything about it. He asked for one though.

Kellermann

When was that? That was a long time ago, I guess.

Matthews

Pardon me, are we talking about the CTC list? Because that I donít have.

Kellermann

Right.

Matthews

No, I definitely- but my other more restrictive list of quasars, I donít have a copy of that either. Martin might. He had a copy of it, I know that. He mentions it in that IAU volume and as far as Iím aware, he was the only other person who had it.

Kellermann

That could be. The big list we all had because we were using that as our observing list.

Matthews

OK, now I must admit that I donít remember the details that went into that. Why wasnít it just the 3CR list?

Kellermann

Because the Owens Valley positions were much better. And so as new positions were obtained, they were put on that list.

Matthews

Ok, but the Cambridge positions from whoever it was and I donít remember his name...

Kellermann

I canít remember either.

Matthews

Well anyway, his positions were damn good, thereís no question. They were equivalent to just about anything we produced.

Kellermann

Hewish? This was later. This wasnít 3C.

Matthews

This was 3CR.

Kellermann

I donít think it was 3CR either.

Matthews

And I think it was a later paper giving positions, maybe just positions, of 3CR, some 3CR sources.

Kellermann

Yeah, thatís correct. Thatís probably correct. But the 3CR catalog mostly just corrected the lobe shifts, as you said, but they were basically the 3C positions. But then they used the 4C instrument, which had much higher resolution, to measure accurate positions.

Matthews

Maybe it was the 4C observation but when did they come out?

Kellermann

A few years later, early Ď60s, and it was in the process of measuring those positions that accidently discovered interplanetary scintillations. And so I think it was Hewish, maybe Paul Scott. Yeah, it was Paul Scott I think.

Matthews

No, this list that I am talking about I think was earlier.

Kellermann

And then ironically, Hewish built that instrument to measure the interplanetary scintillations is the one that discovered pulsars.

Matthews

Right, right.

Kellermann

There were a lot of exciting things that happened then.

Matthews

Yes, there was. I remember that, yeah. You know, what worries me that the graduate student that actually did the observations never got the proper...

Kellermann

Well, she has since.

Matthews

She has since. Reluctantly I get the feeling.

Kellermann

Well, no, no, I think itís widely, widely recognized now.

Matthews

Oh, I think it is but Cambridge certainly didnít recognize it very quickly.

Kellermann

Absolutely. But, in fact, sheís been knighted- well, thatís the wrong word for a woman but she is the equivalent of- sheís a dame of the order of...

Matthews

Is she? No, I didnít know that.

Kellermann

And Iíve gotten to know her. She is a delightful person. In fact, weíve established the Grote Reber medal and she won it last year. She gave a delightful talk at the URSI meeting.

Matthews

You know her then?

Kellermann

Yes.

Matthews

Good for you.

Kellermann

Let me see, she became a professor at Oxford.

Matthews

Not at Cambridge, I know.

Kellermann

When she finished her degree, she went into X-ray astronomy and she had a family and everything so for a long time...

Matthews

You didnít hear much from her.

Kellermann

Thatís right. For the last five, ten years, sheís been very prominent.

Matthews

Good, good. Iím glad to hear that. Youíre telling me all sorts of things I havenít kept up with.

Kellermann

And sheís been, how should I put it- she doesnít have any antagonism towards the Cambridge people. She gives full credit to the people who paid for the instrument and raised the money and everything.

Matthews

Yeah, but I thought getting a Nobel Prize for that- she should have shared in that.

Kellermann

I think many, many people share that view.

Matthews

Yeah, yeah. Itís a pleasure to see you.

Kellermann

Itís been delightful.


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