High-z QSO discussion (Kashik)


Selection method:
Strauss: how about UD layer for high-z QSO?
Kashik: for QSO, UD is too deep (and too narrow) in just 3.5d^2.
Strauss: Is variability selection in deep and UD reasonable for high-z QSOs?
Kashik: Yes.
Nagao: Use of NB for deep is already discussed. Is this useful for higher-z?
Kashik: color selection with NB in combination with BBs is sometimes useful. J is not available in ~1/2 of deep coverage, and NB helps in such cases. The technique also works even for lower redshift QSOs (z<6). For GP selection, it also works (sorry but it was not clear to me).

Spec following-up:
Silverman: any ideas about spectroscopy follow-up plan?
Kashik: we need to come up with a nice strategic program for lower-z/higher-z QSOs and even other faint galaxies.
Strauss: we have PFS!
Kashik: Yes, but for a shorter term, we need a separate plan.
Tanaka: How many nights do you need?
Kashik: need to create a sub-sample for contamination/completeness study so that we can statistically constrain the whole sample. No clear idea how many nights we need.
Strauss: In SSP, we have 300 nights. Can we ask following-up proposals from the same group of SSP while SSP is executing? Is this politically acceptable?
Kashik: I am a TAC chair! I am not sure.
Silerverman: xxx (missed. Sorry)
Silverman: After optical spectroscopy follow-up, we need to go to NIR.
Kashik: We also need multi-band following-up, including X-ray and ALMA.
Silverman: xxx (missed. Sorry)
Srrauss: How about e-Rosetta? How about the data release?
Someone: xxx year (need to check). For their data release plan, I am not sure.
Someone: I expect data reduction and release is very quick. Like within 2 years.
Strauss: As for ALMA, SDSS QSOs have been studied with ALMA, and it was successful with CI (and other lines) for diagnostics. We should consider this.
Imanishi: Is this already published? Should be useful for, e.g., dynamical mass measurement.
Strauss: not yet, but should be soon.
Xxx: How bright it is?
Ranges, including some faintest CFHTQS (need to check) QSOs.


Color selection techniques:
Kashik: our prime idea is to make color-color selection. But one color may be already effective. Refer presentations by Imanishi san and Matsuoka san. But what is the best way for us?
Strauss: The UKIDSS guy who found z=7 QSO (need to confirm) took a robust procedure for their discovery. But variability needs to be taken care properly. Need multiple photometry or something for more robust data.
Kashik: Need to enhance simulation something like Matsuoka san presented.
Tanaka: To be realistic, we need templates, but this is not easy. So the simulation may not be very robust. I suggest, go toward “deep” data first for candidates and do following-up. Thin use the new idea obtained there for selecting “wide” color selections.
Kashik: how is the depth achieved within 1 year? Can we get any useful information during that period?
Tanaka: no idea.
Coupon: what is the risk/fraction in the statistical selection?
Matsukoka: there is always a risk of missing QSOs, but similar risk also exists conventional color-color selection.

J-band photometry.
Kashik: How to include J photometry data for z~7 QSO search? We need to rely on J-band photometry from LAS and VIING. What is our strategy with those data? What is the competition among the teams? Both teams have been keeping working for following-up. What is our plan?
Srauss: Just need to go for it.
Kashik: Our way should be to utilize our HSC optical catalog more for more robust/best QSO selection, and this is our advantage. This is thanks to quality of HSC photometry.

Kashik: How about following-up imaging? For fainter sample, we learned that it helps a lot.
Matsuoka: yes. But no realistic strategy right now.
Nagao: how many nights do we need? But with which telescope?
Matsuoka: xxx
Strauss: systematic errors should be included properly, like bad column and CRs. It depends on S/N: for QSOs with just S/N=5, it will help a lot, but for S/N=10, not so much.
Kashik: Lupton said CR removal can be made perfect.
Straus: We still need to be very careful. Cannot be very perfect if one talks about sources just around detection limit.
Strauss: which telescope do we needed? Subaru is very good, but in many cases 4m should be already powerful enough for following-up photometry.

Science with dwarf stars
Kashik: Any science cases for dwarf stars? More than just by-products?
Matsuoka: LF and Mass-F of dwarfs at sub-stellar mass range. Also Galaxy structure.
Kashik: Our survey area is limited in Galaxy coordinates. Is this really useful for Galaxy structure study?
Strauss: It helps especially when we go very deep, perhaps?
Akiyama: How far can we reach?
Someone: a few 100 pc (less than 1kpc). Deep layer may help pushing limiting distance.
Kashik; Need more collaborators.
Nagao: Matuoka already included some experts in this field.
Matuoka: We are already trying to enhance science cases with local collaborators (at Nagoya?)
Imanishi: I know Dr. Ito (Kobe -> Hyogo) also expressed his strong interests.


1st year science:
Kashik: Imanishi said that it is hard to do something in a year for high-z QSOs. I need to agree with him, but I still want to explore a possibility to publish something. How about presenting simulation and a small fraction of data? How about prompt following-up results just for a very limited number of sources?
Strauss: Discovery is preferred, but need NIR following, etc. But we can do even with just a few sources.
Kashik: Agreed.
Nagao: Takada mentioned that 100 deg^2 (need to check) will be covered in the 1st year. For UD, we can reach sensitivity of D in 1 year. Those are conditions we can expect for the 1st year science.
Oguri: We need to identify the best regions for those sciences. The field should already have other-band data so that we can quickly go forward after HSC data are taken.
Imanishi: Viking field should be selected. There are many useful data already there.
Nagao: Agreed. Indeed we discussed this issue before, but no information is shown in the SSP program.
Ogura: We could not make it before the submission, but we will resume the discussion.
Nagao: good.
Kashik: Yes, VIKING field should be the good one.