Galaxy and AGN Science with CSSOS Linhua Jiang （江林华） Kavli Institute for Astronomy and Astrophysics Peking University （北京大学科维理天文与天体物理研究所） On behave of the CSSOS galaxy and AGN working groups NAOC, Oct 17th, 2017
v Outline § Introduction § Galaxy and AGN science – general Ø Galaxy science Ø AGN science § Galaxy and AGN science – cases § Summary v Some unique capabilities of CSSOS: Ø Deep and wide imaging survey with excellent PSF sizes Ø Multiple bands (7 bands!) Ø Slitless spectroscopy over very wide (and deep) fields Ø Repeatedly imaging and spectroscopic observations (especially in the deep fields)
CSSOS Science over Cosmic History SMBHs, AGN, Quasars Reionization and Environment Protoclusters Morphology Evolution, Clustering Galaxy Adopted from Brant Robertson’s slide, based on Madau & Dickinson, ARAA, 52, 412 (2014)
v Galaxy science in general Ø Structural and morphological studies of galaxies § Wide and deep imaging data with excellent PSF will allow us to study galaxy structure and morphology at redshift between z=0 to z>7 § Size and morphology evolution of (different types of) galaxies across cosmic time § Environment effects: how size and morphology depend on a variety of environmental parameters § Mergers and interacting systems, and their redshift evolution, etc. § Detailed structural and morphological studies of nearby (low-redshift) galaxies, for example, the formation and evolution of bulges and disks 29 hr int. with 4 hr int. with z ~ 0 galaxy, 1 min int. with SDSS Subaru (z band) Keck/DEIMOS 10’’ 4’ (Jiang et al. 2011)
v Galaxy science in general Ø Physical properties of galaxies § Multi-band (7 band) imaging data (plus slitless spectra) will allow us to derive galaxy properties using methods like SED modeling § Physical properties (color, SFR, mass, age, dust, etc.) and redshift evolution of these properties § Galaxy luminosity function and stellar mass function for different galaxy populations, and their evolution § Galaxy evolution, galaxy density field, bias, galaxy quenching, environmental effect, AGN and SF feedback to galaxy evolution, dark matter halo and galaxy properties, etc § For low-redshift galaxies, high-resolution images will allow us to study galaxy outer disk, stellar halo, stellar stream, etc., and perform pixel- based SEDs to obtain spatially resolved stellar populations, spatially resolved mapping of SFR, etc. § ...
v Galaxy science in general Ø Line-emitting galaxies (ELGs) § Deep and wide slitless spectroscopic observations will be very powerful to search for ELGs, such as Lyα emitters, [OII] emitters, and Hα emitters. We will obtain hundreds of millions of ELGs from CSSOS § Physical properties of ELGs and their redshift evolution § Green pea galaxies, BCDs, metal-poor galaxies, etc. § Owing to their secure redshifts, ELGs are particularly useful for studying galaxy clusters and protoclusters § ... Ø Other science cases § The powerful CSSOS will enable many other galaxy-related scientific objectives (a few examples below) § Galaxies and quasars/AGN, galaxy-SMBH co-evolution § High-redshift galaxies and cosmic reionization § Coordinated HI gas survey with FAST § ...
v AGN-related science (from XUE Yongquan, AGN working group) • Host galaxies: properties (color, mass, age, morphology, SFR etc.), galaxy formation mechanisms, AGN triggering mechanisms, M BH -M bulge relation, co-evolution of galaxies and SMBHs • Multiwavelength variability: AGN selection, dependence on AGN properties, correlated variability, physical origins, radiation mechanisms, peculiar transient events, accretion disk theories • AGN strong lensing: identification, structure of central emission region, high-z M BH -sigma relation, faint-end LF, cosmological parameters, properties of foreground objects • Quasar clustering: measurements, dependence on quasar properties, halo clustering, relation between BH accretion and environments • Low-mass BHs: identification, origins of SMBH seeds • etc.
v Galaxy and AGN science – cases SMBH and galaxy co-evolution? (provided by Luis Ho) 1) When? 2) How? 3) Evolve?
v Structure evolution and morphology classification of galaxies (provided by FAN Lulu) Strong size evolution revealed by HST q With CSSOS: • Origin of Hubble sequence • Dramatic size evolution of (specially quiescent) galaxies and its dependence on environment • Morphologies of active galaxies • Etc.
v Galaxy number counts (by SHEN Shiyin) v One of the most fundamental statistical results from the survey v A high precision galaxy number counts statistics in 7 bands provide constrains on galaxy luminosity function, especially the faint end slope galaxy evolution (cosmic SFH and stellar mass assembly history) Calibration of the milky way dust extinction and extinction curve (e.g. Li & Shen et al. 2017)
v Probing Dwarf Galaxies with CSSOS (from FANG Taotao) u Dwarf galaxies: testbeds for galaxy formation - Missing satellites & too big to fail problems … - Why is their star formation so inefficient? - Does reionization photo-evaporate gas in the smallest dwarfs? - Probing the faint end of galaxy luminosity function u CSSOS: a very powerful telescope - Deep survey of dwarfs at the faint-end of the galaxy luminosity function - Discovering hostless transients such as novae and SNe in the local universe (indication of low mass field dwarf galaxies, see right figure) - Mapping the dwarf populations of the Milky Way (and nearby galaxies) Conroy & Bullock (2015)
v Mergers at the low-luminosity end ( from ZHAO Yinghe ) § Dwarf galaxies are more unevolved comparing with massive ones § Construct a large, mass-limited dwarf pair sample with spectroscopic redshifts for BOTH members § We can obtain: § merger rate § star formation properties § Etc. (Stierwalt et al. 2015)
v Studies of resolved stars in nearby galaxies (by SHI Yong) § Multi-color CMD à SFH § A reasonably large sample è Measurements of the star formation history in a statistically meaningful sample; understand the formation of galaxies in the local group Sextans A CMD Dolphin et al. (2003)
v Stellar Mass Functions for different galaxy population and their evolution ( By PENG Yingjie ) Stellar Mass Function by Quiescent and Star-forming Stellar Mass Function by Galaxy Type Ilbert et al. 2013 Moffett et al. 2016
v Slitless Observations of LBGs, ELGs, and LAEs (by ZHENG Zhenya) u HST grism spectra from the GRAPES and PEARS projects u HST ACS/WFC G800L Grism, R~69-131, Avg. z~5 LBG λ: 0.55-1.05 μm. u Composite z ~ 5 LBG spectra from GRAPES (Top), LBG w/o LyA and those w/o LyA (Middle) and with LyA (Bottom). [Rhoads et al 2009]. LBG with LyA u PEARS ELGs [Pirzkal et al. 2013] u Flux limit of 1 x 10 -17 erg s -1 cm -2 , Survey area ~120 arcmin 2 : Ø 174 Ha (0<z<0.49), Ø 401 OIII (0.10<z<0.90), Ø 167 OII (0.5<z<1.6). u With CSST slitless deep survey, we will get tens of millions of these galaxies
CSSOS can select LAEs from z ～ 1 to 7 u LAEs at z>2 are mainly selected from ground narrowband technique. CSSOS will significantly increase the z>2 LAE with much larger area. u LAEs at 1<z<2 are mainly GALEX FUV/NUV grism LAEs selected from GALEX grism observation. CSST will be the most powerful instrument to effectively select LAEs at z ~ 1-2. u CSST Multi-band Imaging & Slitless observations: Ø Physical properties (morphology, SFR, mass, dust, age, etc) and redshift evolution of these properties of LAEs at z ~ 1-7. Ø Using millions of LAEs to trace the large-scale structure and BAO.
Ø Bright - end Lyα LF Reionization Bubbles with CSSOS CSSOS will select luminous LAEs Ø at 1<z<6: luminous galaxies, AGNs, and Quasars at 5.5<z<7: reionization bubbles
Massive galaxy Proto-clusters and galaxy-IGM interactions at z = 2—6 1 Combined with imaging surveys, such as LSST, HSC, we will survey high redshift porto-clusters from different mass (Fernax to COMA progenitors.) MAMMOTH protocluster at z=2.3 (LAE overdensity >=15 on 20 Mpc scale)
2 Combined CSST (redshift info) with DESI surveys (huge Lya forest, CIV, Mg II absorber survey volume), we can study the IGM/galaxy interactions. Seidel +2010 Cai+2017 3 We will directly probe the extended Lya nebula from 50 kpc — 1 Mpc (comoving), which will construct a unique sample of using extended Lya source to map the IGM emission
v High-redshift (z≥6) quasars (by myself) ß Final sample of SDSS z~6 quasars (Jiang et al. 2016) § It took 15 years to obtain a sample of 52 quasars at z~6 § CSST will easily obtain thousands of them, without follow-up identification Numbers of quasars predicted for LSST
(From WANG Junfeng) Science driver - Constraint on AGN active phase and ionizing history - Impact of the outflow and star formation Example: “Hanny's Voorwerp” 25 kpc from main galaxy Identified from SDSS gri images: quasar ionization echo Lintott et al. (2009) ~100,000 years ago CSSOS capabilities highly suitable: Multi-band à effective photometric selection of candidates, and to higher redshift Fine PSF à morphology Large sky coverage à yielding a large sample Spectra à secure identification
So far, only ~20 such objects were confirmed. CSST will be a very efficient machine to hunt for this kind of objects!
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