Exploiting Cosmic Telescopes with RAVEN

Transcription

1 Exploiting Cosmic Telescopes with RAVEN S. Mark Ammons Lawrence Livermore National Laboratory Thanks to: Ken Wong (Arizona) Ann Zabludoff (Arizona) Chuck Keeton (Rutgers) K. Decker French (Arizona) RAVEN Science MACS (M. Postman et al / CLASH team) July 25, 2013

2 Outline 1. Exploiting galaxy clusters as cosmic telescopes for high redshift galaxy detection 2. Two beams from the SDSS with integrated masses exceeding 3 x M 3. RAVEN and ELT MOAO systems will be helpful for: A. Obtaining redshifts of faint multiply-imaged arc candidates B. Searching for high-redshift LAE s along critical curves C. Super-resolving kinematics of highly-magnified galaxies

3 A Few Questions about MOAO for Extragalactic Work 1. How similar are the PSFs in each MOAO arm (if dominated by quasistatic common-path systematics, PSFs may be similar)? 2. How similar is the tip/tilt error expected to be (important for slit losses)? 3. Can second arm be used as a PSF reference? 4. Can second arm be used to compute slit losses for the first arm?

4 Cosmic Telescopes Magnify Distant Sources into Detectability Foreground cluster Gravitational lensing causes massive clusters to act as cosmic telescopes (Zwicky 1937, Soucail+1990). Lensing increases the apparent brightness and size of distant sources, with surface brightness constant. Galaxy in source plane LBNL

5 What reionized intergalactic hydrogen in the early universe? Were bright galaxies at z ~ 6-10 sufficient to cause reionization, or is a contribution needed from large numbers of fainter sources? We need to compute the density of UV ionizing photons emitted from the first galaxies using a measured luminosity function. NASA/WMAP Science Team Nick Gnedin (University of Chicago)

6 The z ~ 7 luminosity function has been largely constrained with blank field surveys Need to know faint end slope of luminosity function to understand contribution of faint galaxies to reionization Faint-end slope appears steep at z ~ 7 Bouwens et al M* appears to decrease rapidly at z ~ 10 Bouwens et al. 2011

7 Lensing Increases Source Counts Dramatically when Unlensed Detection Threshold L* Lensing most helpful when the unlensed survey detection threshold is brighter than or equivalent to L* If depth is sub-l*, lensing only increases source counts if dlogn / dlogl < -2 for resolved sources (HST resolution) and dlogn / dlogl < -1 for unresolved sources (ground-based seeing) Evidence is that dlogn / dlogl ~ -2 (Bouwens et al. 2011) at z > 7 and dlogn / dlogl < -1 at z < 10 (Bouwens et al. 2010, etc.) Ground-based Lyman-alpha emitter searches reach L* at z ~ 7, so cosmic telescope surveys for lensed objects with ground-based telescopes increase source counts most at z ~ 7

8 Multiple Adjacent Clusters Boost Magnification Wong, SMA, et al In lensing simulations, dividing the integrated mass into multiple clusters at different redshifts boosts the area of large magnification Wong, SMA, et al In a 2-halo case with equal mass ratio, the magnification boost is maximized at an ideal projected separation of ~100

9 Dense Beam #2 Sloan Digital Sky Survey (enhanced constrast) Subaru SuprimeCam (stacked filters) 3.3 arcminutes 2 arcminutes

10 Dense Beam #2 The beam possesses four massive structures with 309 km/s < σ < 1138 km/s Most massive structure is a known ROSAT X-ray cluster with σ ~ 1110 km/s and a virial mass of 1.8 x M Integrated mass of all well-sampled structures is 3.1 x M Redshift histogram of most massive structure at z = 0.22 LRGs trace dark matter! LRGs with spectroscopic redshifts Field galaxies Redshift histogram of all structures over 0.1 < z < 0.8

11 Dense Beam #2 JWST NIRCAM field size Magnification map predicts tangential critical curve radius of ~35-40 for z ~ 1 source plane 2x longer critical curves than the most massive CLASH cluster MACS with a virial mass of 3.7 x M Mass model predicts ~100% more sources detected at z ~ 10 than Abell 1689.* Predicted magnification map for z ~ 1 source plane * Assumptions: Bouwens+11 luminosity function and Bouwens observational program (izj-band dropout survey, total integration 60 orbits per beam)

12 Dense Beam #2 JWST NIRCAM field size Predicted magnification map for z ~ 2 source plane

13 Multiply-Imaged Candidates Confirm Integrated Mass and Lensing Model Subaru SuprimeCam BVRiz image (60 x 60 ) Morphologies and SEDs of strongly-lensed arcs suggests that they are multiply imaged If multiply-imaged, arcs would pin the location of the critical curve at 60 away from the cluster (larger than any known cluster) SMA et al SMA et al. 2013

14 Photometric Redshifts of z = 4.95 for Multiply-Imaged Candidates SEDs of multiply-imaged arc candidates BPZ redshift probabilities SMA et al SMA et al % probability of z ~ 5 solution for both multiply-imaged candidates SEDs of candidates match to within photometric errors

15 Multiply-Imaged Candidates Confirm Integrated Mass and Lensing Model Subaru SuprimeCam BVRiz image (60 x 60 ) Predicted z~5 critical curves SMA et al SMA et al RAVEN can confirm redshifts of multiply-imaged candidates

16 RAVEN can obtain redshifts of multiplyimaged arcs at high-redshift (Lyman-alpha) Two natural guide stars are accessible in the field of Zwicky 1953

17 Super-resolution of magnified galaxy kinematics Swinbank+07 (deprojected emission line kinematics) Swinbank+07 SINFONI IFU kinematics obtained for highly magnified arc at z ~ 5 resolution is ~250 pc

18 Summary 1. RAVEN and ELT MOAO systems will be helpful for: A. Obtaining redshifts of multiply-imaged arc candidates B. Searching for high-redshift LAE s along critical curves C. Super-resolving kinematics of highly-magnified galaxies 2. We have found two beams from the SDSS with integrated masses exceeding 3 x M