Deepest Ever Deep Field. Where Are The Limits of James Webb? 

A note from Viraj, "I just saw your video from our interview and think it's fantastic! Thank you so much again. It seems many of your viewers were interested in the planning of future JWST deep field surveys (based on the video title) but that is not my current interest/expertise -- it is something I'd like to help with in a few years after I get a permanent faculty-level position (fingers crossed). But right now, as an early career researcher, thanks to the work of many others who dedicated lots of time to the planning of surveys like CEERS, I have the privilege of focusing my time on thinking deeply about galaxy formation using these amazing observations and by developing new theoretical models (like what we discussed in the first half of the video). I highly recommend getting someone from the JADES team on your podcast -- they are at the current frontier of JWST deep fields so will know much more than me about what is and isn't possible over the next few years (as I said, I'm focused on the science itself). They've already surveyed areas including and surrounding the Hubble Deep Fields North and South. As discussed in section 4.1 and Table 1 of Eisenstein+23 (arXiv:2306.02465), some of their deepest imaging in any particular pointing and in any single filter is of order ~10 hours which is a factor of ~5 lower than the deepest single pointing (in a single filter) from the latest "Hubble Legacy Field" (Whitaker+19). And yet as Figure 5 from Eisenstein+23 beautifully shows, this ~10 hour JWST imaging is already much more sensitive than the deepest single ~65 hour Hubble Legacy Field imaging (at a similar wavelength). There is also another "JADES Origins Deep Field" (Eisenstein+23, arXiv:2310.12340) whose deepest single pointing (in a single filter) may approach or even exceed the deepest single-pointing, single-filter HDF images with 50+ hours. On top of this, they are investing a significant chunk of time on spectroscopy -- I discussed the importance of spectroscopy in the first half of the video for, e.g., constraining the kinematics of stars/gas in low-mass high-redshift elongated galaxies. You can probably extrapolate what will be possible for JWST Deep Fields over the ~15-20 year lifetime of JWST based on the incredible work that JADES has done. I also wanted to clarify that I mis-spoke at ~37:30. The HST-CANDELS program was ~2 months total of observing time but that was split among 5 fields, and there is nuance in the depth of individual pointings (in individual filters) in any individual field. In other words, not all tiles for the mosaic in a single field have the same exposure time. For GOODS-S and GOODS-N (which contain the HDF-S and HDF-N, respectively), some of the deepest imaging is indeed ~50+ hours in a single pointing (in a single filter). For the wider (shallower) parts of CANDELS in the UDS, EGS and COSMOS fields, the depth drops to a few hours at most in a single tile with a single filter. This nuance is important because it can be confusing to say that a deep field was "100s or 1000s" of hours -- indeed, the latest Hubble Legacy Field in GOODS-S (containing HUDF) has a total exposure time of 6.3 Megasec ~ 1750 hours, but what's more useful from a practical point of view is to quote the *range* of exposure times in a single filter over the full survey area (as nicely shown in Figure 1 of Whitaker+19). For example, the original Hubble Deep Field was 140 hours (Table 5 of Williams+96) but that was split into ~30-40 hour images in four different filters -- this was unprecedentedly deep in individual filters and only feasible because they didn't do a mosaic (effectively just a single tile/pointing)." Sincerely, Viraj

Normally interviews like these don't really captivate me but, Fraser does a really good job with the questions that he asks that I can't stop listening, it also helps when you have really interesting guests like Dr Pandya. I can't wait for the next one.

That's the first time I've heard somebody being interviewed saying "thanks. It's been a lot of fun." For an esteemed scientist to say that to you greatly impresses me. Congratulations Fraser!! And greetings from Thailand.

You are hitting home run after home run with your interviews. The guests are highly knowledgeable, are great communicators, topics are very interesting, and you're asking high quality questions. I think you're doing a wonderful job and sincerely thank you for bringing such high quality Science for presentation on YT. 👏

This was a fantastic interview. You can tell Dr. Pandya loves and is excited about his work.

These recent interviews are awesome and your questions and reasoning are great. Well done Fraser.

The exposure length limits due to background light is addressed in a JWST Science Working Group paper titled The Scientific Capabilities of the James Webb Space Telescope. It is available on-line as a pdf.

Dr. Pandya's food analogies absolutely work for me! 🤣 Thanks for these interviews, Fraser. Please, never get tired of doing them!

The Hubble Deep field, as wonderful as it is, only took 100 hrs, not thousands. However, I love these interviews. Great to get the insights of experts actually working on and with these projects. 👍

Great interview and interviewee, yes. Impressive when someone successfully conveys their visualisation of dynamics.

Great you tube with a great subject. Definitely the best work on Galaxies I have seen so far

I agree with Fraser. If waiting for Roman to come online and having that ability to do a wider range view prior to a James Webb deep field, this will allow for a better targeting range for Webb to deep field and whether a longer/shorter exposure is needed. JW has plenty of science to do before that decision is needed. Besides, they can do both w/a shorter exposure now and after Roman is alive, proceed w/a longer more targeted exposure then.

I've never commented before, but had to for this. Viraj was far and away one of the best interviews I've seen - wonderfully knowledgeable, thoughtful, and so interesting. And Fraser excellent as always. Thanks for all you do, and hoping for a follow-up interview with Viraj someday!

Another great interview, "Deepest Ever Deep Field", that I could not stop listening to! It would be most helpful to my limited, linear mind, to see pictures flashed up on objects being discussed, e.g. Hubble deep field view, bread stick galaxies, 15 red shift galaxies, and even such 'mundane' things as Red Dwarf, Blue stars?, edge on elliptical galaxy, etc, etc....

I liked Viraj's attitude... just straight up admitted when he didn't know something, and then demonstrated interest in the question?

Loved it as usual. It's sometimes hard to click on these instead of some anger-inducing drama. But I'm always happy that I clicked

Great interview. You guys did a great job of painting a pictures for me. Thank you!

This is a great interview. Thank you Fraser and Dr. Pandya.

This discussion with Viraj is so interesting . Cain is a GREAT Interviewer, and the discussion is deep but so clear. Thank you for doing this!

Fascinating insights into the cosmos! Thank you for sharing, I thoroughly enjoyed the information. Sending love from Ontario Canada. ❤️🎶🍁

Great interview, thanks both of you.

I'm in the middle of watching this interesting video, and the discussion of the breadstick shape evolving to the spirals we're familiar with has ended. Probably no one knows, but I'm wondering whether the bar in barred spirals is a remnant of that breadstick.

Great topic, thanks for the interview! Also this is one of few interviews I need to rewatch becsuse the ammount of new information and thought experiments. I think the large structure of the universe should get more time on this channel, it's so fascinating!

Absolutely fascinating...again! Thanks to all involved.

Captivating interview, well done, that was fascinating.

Thank you for a plethora of great content

Absolutely loved this discussion. Fascinating! ❤️

I learned soooo much on this one! Ty ty ty Fraser!

Bless you to the person in the background.

Perfect for a Sunday mornings viewing

So often, my hobby - aspiring to be an autodidact, polymath, polyglot, Renaissance man, and natural philosopher - makes me feel stupid. Like when I set my curtains on fire with a laser or blow the door off my shed making rocket motors. In fact, feeling daft is a good thing, as the Dunning-Kruger effect tells me. Yet, it is always a joy to feel clever after watching Mr. Cain's video content. His penetrating questions and fantastic subject matter are much appreciated. Thanks.

This discussion is SO cool!!

Great interview, great interviewee

I found this very useful and informative. The "breadsticks" speculation is a useful testable concept.

Interviews are my favorites

Amazing interview

Excellent informative and interesting interview. I enjoyed the insightful questions and the straightforward answers. Fraser, your questions do a great job of helping guests with painting the big picture as well as extracting meaningful, supportive details. And your steady stream of articulate leaders in each field is also superb. Best interview so far. I am amazed that there are breadstick galaxies. Keep up the excellent work.

Thank you for a wonderful discussion.

43:41 i think this was a perfect answer Fraser, the diminishing returns starts with the overlap of ROMAN. There is no point in wasting JamesWEB time on something that newer telescopes will be able to do exponentially faster.

Awesome interview!!

great interview

Great video. Also, your only video that has made me hungry haha.

Fraser Cain is such a great choice for explaining the Hubble and James Webb ultra deep field images. His sentences are clear and informative. I’m glad he is our guide!

We want more and soon. Thanks to Vijar 😊😊

Honestly I would have expected your guest to know the answer to the limits question as it’s something I’ve wondered myself and seems fundamental to the field. The fact that it hadn’t even occurred to him is surprising.

Dude that was great!

You're amazing Fraser, the stuff you know is scary.

Awesome topic and guest. How was this not one of the first things JWST did? It would be the most incredible thing ever. Really interesting discussion

Well done. Thank you.

You and Viraj both have infectious passion and this has been great to watch and listen to! Also agreeing with a comment below, Dr. Pandya's analogies are perfect lmaoo

I just want to thank you all for the knowledge shared and insights in the journey so far with JWTS along with the gifts from the images and what we know so far. I appreciate the educational aspects too by the bucket load along with the additional comments from Viraj and others commenting on what is really needed to get understandable information. I am not educated in any way but only want to say thank you for what you share as I still catch my breath at moments in my life time.

I've used the ultra-deep field Hubble image for years as my desktop wallpaper!

exciting times, especially with the studies being done on the age of universe being twice as old as we thought!

Thanks Fraser. You could tell that he loves what he does.

Fraser, the satellite galaxies are the peperami flying off the rotating pizza 🥴

So through the direction of those early breadstick shaped galaxies, you can map the dark matter filaments. It’s quite a feat to be able to map these filaments and intersections that we can’t even see. You guys are doing extraordinary stellar work! p.s. Just stumbled upon your channel, it’s doing a great job at explaining this information in a comprehensible manner to novices, like me. Thank you! I also enjoyed listening to Dr Viraj Pandiya.

Incredible! Ty

God bless you **(to the sneeze)

omg is this guy pleasant and chill 😎👍

Im not much for interviews but that was great.

The popping in to existence is the key to the wavelength of a mass ejection points they lost there energia but continue on with the barometric pressure that no vibration system that electrons flows through from point to point interactions

The Hubble deep feild was a little over 100 hours of exposure time. Not thousands of hours.

Bless you 😊 18:00

I confess I was aching for a visual of a breadstick galaxy.

What about EUCLID? Seems to have a similar mission to Roman. How will they work together, and with webb?

I think that the 15 min with JWST vs. 50 days Hubble is mostly explained by the fact that the far away galaxies are seen in great part in infrared that JWST is designed for, Hubble being designed for visible (and ultra v)..

42:00 What is the noise floor on the sensors? Would ten 100 hour exposures look different than 100 ten hour exposures?

I would like to see an ultra deep field view 180 deg from Hubbles original...!

So do we have any galaxies that we *know* are breadstick galaxies, and if so, what is the closest one? Is there any reason we should be finding these in the distant past but not in contemporaneous time?

Very interesting. Have you read Time Waves on the Shores of Forever, lots of similar ideas..

I was startled when Dr Pandya suggested dark matter in a filament was responsible for the breadstick shape of some early galaxies. In my astronomy study the cosmic web was a filamentary network composed of filaments, sheets, knots and voids. I understood voids are vast empty regions, knots are massive galaxy clusters, and filaments and sheets connect the knots. Filaments were highways or transport channels that channelled mass and galaxies into higher density cluster regions. It makes sense that the cosmic web can outline and reveal the locations of dark matter. If merging dwarf galaxies are drawn into a filament this may explain the breadstick shape of the resulting galaxy. But filaments are present in the early and late universe, why are breadsticks only seen in the early universe?

The measure of our atmosphere of Aurora and how gases react to the wavelength of energy within the surface densities to matching the temperature of other planets around us

That is amazing! All the Astronomy details and searches that are planned!. All this time I was shaking my head at the U.S. Military for using so many Acronyms . And then here comes C.e.e.r.s. lol I guess we will never be without tons of acronyms in our life lol. Thank you Fraser.

When or wen?!!

The "breadstick" observation feels so much like an artifact of the way we're observing, in a universe with lensing, expansion, time dilation, etc. But experts would know a lot better than I would.

Oh man I'm looking forward to this. Also is like like matter and the void or dark matter are like oil and water in a way?

cool workds is getting time to look for exoplants

Realy I likethisvideo so much like you can imagine

Not doing a deep field with WEB is like not looking for the Higgs particle with the LHC.

So the tubular shapes of early galaxies are due to dark matter filaments of some kind? That's insane! Could these be the footprints of superstrings? I'm thinking of the various anomalies the Enterprise-D encountered of course!

Nice interview, thanks! If we actually discover this empty space (behind the edge of our universe) with an advanced telescope that reaches and observes even further than the JWST or Hubble ST, it will only be because the general collapse of matter of the previous universe took place there, the so-called Big Rip or Big Freeze. However, this period would be limited, depending on how long the predecessor's dying process took... Even in the Voids there are far fewer or hardly any stars and galaxies or clusters than in other areas of the universe - I think the reason is that at the very beginning of the cosmos there were many small pocket universes, or rather small bubble multiverses, which later all merged into one single gigantic universe, so these are unfilled spaces from a previous border zone... Then to the mysterious dark matter - the “glue” that holds galaxies together. I'm not so sure whether it really exists. At least I think the word “dark matter” is wrongly chosen; I would call these phenomena or force "space-connecting gravity"... 🌀

Question, can there be a correlation with the bar in the center of the pizzas and your breadstick?

Very interesting. But, wat is with the wen? Sorry, what is with the when?

When i was in crystal caverns I was reading the whole flow of light as inferred in the darkness the high level of heat was so unbearable that I was affecting by the densities of the deeper layered material sometimes seemed to be more intensely consitrated with the reflection of fractional energy the more weaker states of the higher ones were more likely to be blocking the system of light

I like this video so so much its incredible

The Universe is endless ... it just goes on, and on, and on.

Are you accounting for the time lapse factor? Is it even significant at those distances? A doughnut could stretch out to a breadstick depending on orientation…

I thought that they already did a comparison of the Hubble's Deep Field and the Webb's Deep Field! No?

Question: can the lack of star formation in galaxies in denser clusters be a Fermi paradox solution? "Galactic supercluster habitable zone"

19:23 wow!

Bread sticks could be the plasma beams of mass ejection points of slowed down spin and densities filled in the spacing process circles within circles of billions of particles in the pathways itself

By looking back further in time, it seems that astronomers are uncovering the evolutionary path for galaxies: originally tubular, then disc-shaped, then spherical. The early tubular galaxies may “point back” to their common origin (at 23:40) … Considering tubular galaxies as the forerunners of spiral galaxies suggests (hypothetically) that the tubular galaxies eventually develop into the *arms of spiral galaxies, and eventually collapse (merge) into the sphere of the most mature galaxies. The analysis presented in this interview (at about 21:00 minutes) suggests that dark matter was well-established throughout the universe *before the Big Bang, and that ordinary visible matter (stars, galaxies) got caught up in the dark matter field (filaments) while being propelled away from their origin. If that is the vision, then the Big Bang is not “the beginning” of the universe, but a phenomenon that emerged *within the earlier dark matter universe. If dark matter did precede visible matter, it suggests another hypothesis: ordinary matter is derived from - perhaps fractional pieces of - dark matter. This chain of logic suggests that an all-dark matter universe may be slowly evolving into a visible matter universe

I would not put anything past looking longer at something. In other words, they may not be a point of diminishing returns. When the Hubble Deep Field was done, I'm sure everyone figured there would be little to nothing there, but then, bonk! I don't see why the same wouldn't be true for holding the Webb looking at the same spot as Hubble for the same amount of time and being further wowed by what is observed! When I first saw the Hubble Deep Field photo, I was just sitting at my desk alone and my jaw hit the ground as I realized I was looking at hundreds of galaxies!!! Hubble for me proved its worth in that moment!

Hey Frasier, the moon regolith is known to be really rough on space equipment, plants, and lungs. Is there some kind of device like a rock polisher that could be used to make it safer for things like plants?

Actually, I had assumed that by now a JWST deep field had already been done. Please do some in pairs, 180 degrees from each other so comparisons can be made. I would like to know if there are similarities at opposite sides of the universe - or are they wildly different?

When you look at another galaxy, stars which are one behind the other in our line of site are shaded out. The near one shades out the further ones. We judge the mass of a galaxy by the amount of light (and other EM radiation) coming from it. How is this shading effect taken into account. Could at least part of the dark matter actually be an under-estimate of the mass of a galaxy.

Maybe mathematically how far we can see is when density blocks out any further sight line? So theoretically we could determine the max time we can see back? And use that as the time we would need to stare at one point. Guess more of a question than an answer.

I have a naïve question about the distance ladder. I gather that the first rung of the ladder is dependent on parallax measures of distances to Cepheid variables to get the absolute luminosities of the stars and these measurements are limited by the size of the base line constituted by opposite sides of the earth’s orbit around the sun. I’ve wondered whether astronomers have also tried comparing current star fields to historical photographs from say 100 years ago to get a longer baseline constituted by the distance traveled by the earth around the center of the Milky Way during that time. If that were doable, it would seem that it would refine the distances to the stars already measured by the standard method, and would extend the sphere in which Cepheid variable distances could be measured. Is that something that just hasn’t been done because it’s not practicable due to the difference in technique over time, or due to the fact that you could only get one measurement, rather than repeated measurements as you could using the earths orbit, or are such measurements part of the current understanding of the first rung of the latter?

So, is it like a stream of water breaking up into individual droplets as water falls / the universe expands? That process, could start with the dark matter, and star formation develop later to make it visible.

I loved the latest episode of the James web satellite these gas disks are so caught in a dance from other ones that have an opposite spinning direction and then when these get images get better there's a symitry in circulation of others and joining to build up and slows down the fluid dynamics streaming some areas are standing still in spin rotations but they are already ones that have joined an array of light