STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

1. STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P Lyman-α Emitters at 2<z<4 Guillermo A. Blanc The University of Texas at Austin Spiral Galaxies at z=0 IFUs in the Era of JWST, STScI, Baltimore – 10/28/2010

2. The Hobby-Eberly Telescope Dark Energy Experiment

3. MPE/USM: Ralf Bender Niv Drory Ulrich Hopp Ralf Koehler Helena Relke Jochen Weller University of Texas: Josh Adams Guillermo Blanc Mark Cornell Taylor Chonis Karl Gebhardt (PS) Lei Hao Gary Hill (PI) Eiichiro Komatsu Hanshin Lee Phillip MacQueen Jeremy Murphy Marc Rafal (PM) Masatoshi Shoji Texas A&M: Darren DePoy Steven Finkelstein Jennifer Marshall Nicolas Suntzeff Other: DonghuiJoeng (Caltech) Eric Gawiser (Rutgers) PovilasPalunas (LCO) AIP: Andreas Kelz Volker Mueller Martin Roth Mathias Steinmetz Lutz Wisotzki Penn State University: Robin Ciardullo Caryl Gronwall Larry Ramsey Don Schneider

4. The Hobby-Eberly Telescope Dark Energy Experiment • HETDEX will measure the power spectrum for 800,000 Lyman Alpha emitting galaxies (LAEs) at 1.8< z <3.5 over a volume of 3 Gpc3. • From the power spectrum HETDEX will measure w(z)=pDE(z)/ρDE(z) with a 1% accuracy and the curvature “k” with a 0.1% accuracy at z=2-3 • High-z measurements are complementary to low-z measurements and allow to study evolution.

5. MUSYC LAE in E-CDFS, R=25.7, z=3.085 Ly EW=200Å, (6 hr IMACS exposure)

6. You get a spectrum for every arcsec2 patch over 60 deg2 and you check if you see one. • How do you find 800,000 LAEs? i.e. You use VIRUS Visible Integral-field Replicable Unit Spectrograph

7. 100” 15.6’ VIRUS consists of 75 IFUs feeding 150 spectrographs on the HET 9.2m

8. VIRUS will be commissioned on early 2012

9. VIRUS-P: The Prototype • VIRUS Prototype IFU • 1.7’x1.7’ FOV at McDonald 2.7m • 1/3 filling factor • Largest FOV of any existent IFU • 4.2’’ diameter fibers on sky • 3500-5800Å wavelength range • Ly-Alpha @ 1.9 < z < 3.8 • R=1000 @ 5000Å

10. The HETDEX Pilot Survey • SURVEY DESIGN: • 169 arcmin2 surveyed on COSMOS, GOODS-N, MUNICS-S2, and XMM-LSS fields • Fields selected to have deep multi-wavelength broad-band imaging • 6 position dither pattern ensures good field coverage • Three 20 min exposures at each position • 2 hr of effective exposure time • 5σ flux limit of ~6x10-17 erg/s/cm2 for a point-source emitting and unresolved line • Adams et al. 2010; Blanc et al. 2010, Finkelstein et al. 2010 (next week on arxiv) • GOALS: • HETDEX and VIRUS proof of concept • Create an LAE sample spanning a large redshift range, to study the properties of LAEs and the escape fraction of Lyα photons from galaxies, and their evolution with redshift.

11. DETECTION OF EMISSION LINES • GROW DETECTION UNTIL S/N STOPS INCREASING • POSITION GIVEN BY FIRST MOMENT OF LIGHT DISTRIBUTION

12. SOURCE CLASSIFICATION • 2 step classification: • Classification based solely on the spectrum • Use broad-band flux of counterparts and Lyα line flux to apply EWrest> 20 Å criteria. TYPICAL NARROW-BAND

13. LYMAN ALPHA EMITTERS Low-z GALAXIES

14. 98 LAEs at 2<z<4 !!! and ~400 low-z galaxies and AGN

15. Dust and the escape of Lyα q = (Lyα/ λ=1216) • Favorable ISM configuration reduces Lyα quenching by dust. • No evidence of EW enhancement by clumpy dust distribution in multi-phase ISM. • LAEs fall above LBGs and should be considered as an upper envelope for the overall galaxy population.

16. Lyα Luminosity Function

17. THE GENERAL GALAXY POPULATION Lyα ESCAPE FRACTION • Estimated by predicting Lyα luminosity expected given the SFR density history of the universe, and comparing to the integral of the Lyα Luminosity Function. • Sharp transition from 100% down to 5% between z=5 and z=3. Best-fit transition redshift of 4.1 0.5 • Most likely due to dust build-up in galaxies. Blanc et al. 2010 (submitted to ApJ) Bouwens et al. 2009

18. HETDEX SAMPLE • HETDEX is a blind spectroscopic survey of 60 deg2. • 800,000 LAEs at 1.8<z<3.5 • 1,000,000 [OII], Hβ, [OIII] Emitters at z<0.5 • 400,000 continuum galaxies • 250,000 MW stars with spectra • 2,000 galaxy clusters • 10,000 – 50,000 AGN at z<3.5 • 10,000 LABs • And whatever it is we are not looking for!!!!!!

19. P.I.: Guillermo A. Blanc (UT, Austin) Co.Is: Niv Drory (MPE, Garching) Neal Evans (UT, Austin) Maximilian Fabricius (MPE, Garching) David Fisher (UT, Austin) Karl Gebhardt (UT, Austin) Lei Hao (Shanghai Observatory) Amanda Heiderman (UT, Austin) Gary J. Hill (UT, Austin) Shardha Jogee (UT, Austin) John Kormendy (UT, Austin) Irina Marinova (UT, Austin) Juntai Shen (Shanghai Observatory) Remco van den Bosch (UT, Austin) Timothy Weinzirl (UT, Austin) Mimi Song (UT, Austin) • 32 Nearby Spiral Galaxies • 72 1.7’x1.7’ VIRUS-P Pointings • ~ 53,000 spectra: 3600 Å – 6850 Å • Spectral Resolution: 5 Å (120 km/s) • Coverage > 0.7 R25 for all galaxies • Median S/N=40 per fiber • High Resolution VIRUS-W (25 km/s)

20. MOTIVATION GAS ACRETION (HOT/COLD) • HOW DO GALAXIES FORM AND EVOVLE? FEEDBACK (SN, AGN, STARS) SECULAR PROCESSES SFR (BURST/ GENTLE CYCLE) MERGER (MAJOR/MINOR)

21. NGC 5194 (Blanc et al. 09) 4 kpc

22. CENTRAL AGN Crane et al. 1992 Bradley et al. 2004

23. DIFFUSE IONIZED GAS • DIG accounts for 11% of total Hα luminosity WHAM (Madsen et al. 2006)

24. LOCALIZED STAR FORMATION Hα HII Regions + DIG HII Regions Only

25. VENGA Blanc et al. 2010 THINGS Walter et al. 2008 BIMA SONG Helfer et al. 2003

26. RESULTS • 735 regions (D=170 pc) in the central 4.1 × 4.1 kpc2 • Lack of correlation with the atomic gas surface density, which saturates around 10 Mpc-2 . • Clear correlation with the molecular gas surface density, which drives the total gas SFL • Monte Carlo Fitting of total gas SFL parameters: • N = 0.85 ± 0.05 • A = 10−1.31±0.02 = Depletion timescales of 2 Gyr • ε = 0.43 ± 0.02 dex. • Consistent with a roughly constant SFE in GMCs, which is almost independent of the molecular gas surface density. NOT consistent with a N~1.5 slope. • Good agreement with the theoretical SFL model of Krumholz et al. (2009).

27. ONGOING AND FUTURE WORK • Extend analysis to the full VENGA sample: • Sample different regimes in density, Z, dynamics, etc. • Intrinsic Scatter: • Search for extra parameters • Scatter in SFR indicators • Scale dependence and connection to MW studies. • Extend study to denser environments in starburst and mergers: • Non-linear regime of the SFL • VIXENS (P.I. Amanda Heiderman)

28. VENGA MAP OF NGC 2903 THANK YOU!!