STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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

description

STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P. Lyman- α Emitters at 2

Transcript of STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

Page 1: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

Guillermo A. BlancThe University of Texas at Austin

Lyman-α Emitters at 2<z<4 Spiral Galaxies

at z=0

IFUs in the Era of JWST, STScI, Baltimore – 10/28/2010

Page 2: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

The Hobby-Eberly TelescopeDark Energy Experiment

Page 3: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

MPE/USM:Ralf Bender

Niv Drory

Ulrich Hopp

Ralf Koehler

Helena Relke

Jochen Weller

Penn State University:Robin Ciardullo

Caryl Gronwall

Larry Ramsey

Don Schneider

AIP:Andreas Kelz

Volker Mueller

Martin Roth

Mathias Steinmetz

Lutz Wisotzki

Texas A&M:Darren DePoy

Steven Finkelstein

Jennifer Marshall

Nicolas Suntzeff

Other:

Donghui Joeng (Caltech)

Eric Gawiser (Rutgers)

Povilas Palunas (LCO)

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

Page 4: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

• 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.

The Hobby-Eberly Telescope Dark Energy Experiment

Page 5: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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

Page 6: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

• How do you find 800,000 LAEs?

i.e. You use VIRUS

Visible Integral-field Replicable Unit Spectrograph

You get a spectrum for every arcsec2 patch over 60 deg2 and you check if you see one.

Page 7: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

VIRUS consists of 75 IFUs feeding 150 spectrographs on the HET 9.2m

100”

15.6’

Page 8: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

VIRUS will be commissioned on early 2012

Page 9: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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

Page 10: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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:

1. HETDEX and VIRUS proof of concept

2. 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.

Page 11: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

DETECTION OF EMISSION LINES

• GROW DETECTION UNTIL S/N STOPS INCREASING

• POSITION GIVEN BY FIRST MOMENT OF LIGHT DISTRIBUTION

Page 12: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

SOURCE CLASSIFICATION

• 2 step classification:1. Classification based

solely on the spectrum

2. Use broad-band flux of counterparts and Lyα line flux to apply EWrest> 20 Å criteria.

TYPICAL NARROW-BAND

Page 13: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

LYMAN ALPHA EMITTERS Low-z GALAXIES

Page 14: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

98 LAEs at 2<z<4 !!!

and ~400 low-z galaxies and AGN

Page 15: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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.

Page 16: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

Lyα Luminosity Function

Page 17: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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.

Bouwens et al. 2009 Blanc et al. 2010 (submitted to ApJ)

Page 18: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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!!!!!!

Page 19: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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)

Page 20: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

MOTIVATION• HOW DO GALAXIES FORM AND EVOVLE?

FEEDBACK (SN, AGN, STARS)

SFR (BURST/ GENTLE CYCLE)MERGER (MAJOR/MINOR)

GAS ACRETION (HOT/COLD)

SECULAR PROCESSES

Page 21: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

NGC 5194 (Blanc et al. 09)4

kpc

Page 22: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

CENTRAL AGN

Crane et al. 1992

Bradley et al. 2004

Page 23: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

DIFFUSE IONIZED GAS

WHAM (Madsen et al. 2006)

• DIG accounts for 11% of total Hα luminosity

Page 24: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

LOCALIZED STAR FORMATION Hα

HII Regions + DIG HII Regions Only

Page 25: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

THINGSWalter et al. 2008

VENGABlanc et al. 2010

BIMA SONGHelfer et al. 2003

Page 26: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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 Mpc-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).

Page 27: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

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)

Page 28: STUDYING STAR FORMATION ACROSS COSMIC TIME WITH VIRUS-P

VENGA MAP OF NGC 2903

THANK YOU!!