Intense starbursts at z ~ 5

1. Intense starbursts at z~5 First significant stellar mass assembly in the progenitors of present-day spheroids Aprajita Verma University of Oxford Matt Lehnert (GEPI), Laura Douglas (GEPI) Natascha Förster Schreiber (MPE), Malcolm Bremer (Bristol)

2. Aprajita Verma - LAE08 Heidelberg 10/08

3. Total Area ~ Subaru Deep Field spread over 12 independent fields Cosmic Variance (but might not be enough, Masami Ouchi's talk) Verma et al. 2007 MNRAS 377 1024 Douglas et al. in prep Douglas PhD thesis Aprajita Verma - LAE08 Heidelberg 10/08

4. GOODS/CDFS V-band dropouts VAB-iAB>1.7 SNR(B)<3 iAB<26.3 reaches UV luminosities of z~3 LBGs (AB<25.5) 4.6 < z < 6 109 candidates Aprajita Verma - LAE08 Heidelberg 10/08

5. HST viz images of GOODS/CDFS V-band drops r1/2 ~ 1kpc Aprajita Verma - LAE08 Heidelberg 10/08

6. zsp=4.44 zsp=4.90 zsp=4.50 GOODS/CDFS V-band dropouts Verma et al. 2007, Verma et al. in prep Aprajita Verma - LAE08 Heidelberg 10/08

7. Properties of z~4.8 LAEs See posters by Yuma et al. & Ohta et al. Mass: 8.4  108M Age: 17 Myr SFR: 82 M/yr Extinction: ~0.09mag No obvious trends of these properties with presence of Ly Ensemble Properties of z~5 LBGs in the CDFS High redshift : 4.4 < zphot < 5.6 Moderate stellar masses : few  109M Young ages : < 100 Myr High SFR : Few-several 10s M/yr Low extinction : Av~0.3mag Compact: rUV ~ 1kpc e.g. Egami et al. 05, Chary et al. 05, Dow-Hygelund et al. 05, McLure et al. 06, Eyles et al. 05,07, Yan et al. 06, Stark et al. 06, Pentericci et al. 07 etc. Aprajita Verma - LAE08 Heidelberg 10/08

8. Few 109M 320Myr 1010M Few 10s Myr z~3 Shapley et al. (01) 74 LBGs with AB<25.5 z~5 Verma et al. (07) ensemble properties of LBGs with iAB<26.3 ~1mag Several 10sM/yr ~0.3mag The average SED of z~5 LBGs is "bluer" than at z~3 Hathi, Malhotra & Rhoads 2008 Comparison to luminous z~3 LBGs Unequivocal change in the properties of LBGs at z~3 and z~5 Young and moderately massive systems comprise <30% of the z~3 population but dominate ~70% samples of the z~5 LBGs Modelling assumptions: Bruzual & Charlot (03) Salpeter IMF CSF Z=1ZZ=0.2Z Calzetti extinction law SMC extinction law Aprajita Verma - LAE08 Heidelberg 10/08

9. Incompleteness: Magnitude & redshift Faint end of LF =-1.7 (z~3 LBGs) Star formation rate density determined using full SED SFR/L(UV) declines with age for age<100 Myr Förster Schreiber et al. in prep. Aprajita Verma - LAE08 Heidelberg 10/08

10. Incompleteness: Young : Stochastic <Age> ~ 25 Myr tlookback~ 325 Myr Duty cycle only ~1-in-13 detected Cstoc? >0.3% of stellar mass in place at z~5 Stellar Mass Density ~1.5% of stellar mass in place at z~5 Aprajita Verma - LAE08 Heidelberg 10/08

11. YOUNG median age ~few x 10 Myrs SF has been proceeding for ~ one-few tdyn Local starbursts: large-scale SF events of comparable durations First large-scale stellar mass assembly tdyn≈ r/v = √(r3/GM) SMALL median 1/2 light radii ~1kpc MODERATE MASS median mass ~ few x 109 M Geometric factor ~3-5 tdyn~ 10Myr ‘galaxies-in-formation’ at z~5 Aprajita Verma - LAE08 Heidelberg 10/08

12. High concentration, big Balmer break Low concentration, small Balmer break High stellar mass surface densities …not high stellar masses!  > 3 x 108Mkpc-2 Regime of spheroids & bulges independent of the stellar mass of the systems (Kauffmann et al. 2003, 2006) z~5 ~ 4 x 108Mkpc-2 similar to bulge/spheroidal components of present-day L* galaxies (Galaz et al. 02) Dynamical evolution towards higher densities, larger masses … growing in bursts of star formation … towards massive spheroids … Late Type Early Type Kauffmann et al. 2003 Aprajita Verma - LAE08 Heidelberg 10/08

13. Lehnert et al. 2007 Songaila 06 Ryan-Weber et al. 07 Intensity of UV selected starbursts over a range of epochs log SFR (M yr-1 kpc-2) Winds Papovich et al. (2001), Heckman et al. (2001) Redshift High-z IGM High SF intensity SFR~1 to 100 M/yr/kpc2 (local SFI requirement for superwinds >0.1M/yr/kpc2 Heckman 2001)  Strong outflows / Winds (cf z~3 LBGs Shapley et al. 2003)  Contribution to the early enrichment of the high-z IGM Young ages  Material reaches local IGM  Inhomogeneous/inefficient metal mixing on intra- and inter-galactic scales  Possible fraction of metal free SF (Jimenez & Haiman, 2006)? Aprajita Verma - LAE08 Heidelberg 10/08

14. VRI HST V R I z J K ESO Remote Galaxy Survey VLT Large Program PI Malcolm Bremer Z+spectroscopy of 10 EDisCS Survey cluster fields (VRIJK) R-drops: R-I>1.3, IAB<26.3 64 confirmed at 4.4<z<6.4 including - 36 "Ly-emitting" and - 28 "break-only" galaxies R~660 z=5.49 Aprajita Verma - LAE08 Heidelberg 10/08

15. The most massive galaxies formed earlier and faster in high density environments Thomas et al. 2005 Tip of the iceberg?! Considerable field-to-field variation in surface density. e.g. in 10 fields each of 40 sq. arcmin., number of spectroscopically confirmed sources varies between 3 and 11 per field (Douglas et al in prep). …but not in the spatial distribution Their separation (670kpc) is too great to be dynamically bound or interacting. Trace underlying matter distribution? If the starbursts we are seeing produce stars that end up in the most massive systems today, there must be much more material at the same redshifts as these systems that is, as yet, undetected. Gas to be processed in high-z ISM/IGM or obscured/dark SF galaxies? Two richest fields show coherent structure in redshift distribution… - starbursts are synchronised (if age<few 10s Myr) Promising sites to search for dark (or UV faint/obscured) baryonic matter using future IR-cm facilities Douglas et al. in prep. & Douglas, PhD thesis Aprajita Verma - LAE08 Heidelberg 10/08

16. ERGS - Breaks vs. Emitters Are LAEs a better tracer of large-scale structure than LBGs? Aprajita Verma - LAE08 Heidelberg 10/08

17. ERGS - Breaks vs. Emitters Breaks redder than line emitters Aprajita Verma - LAE08 Heidelberg 10/08

18. E-ELT/HARMONI & LAEs Integral field spectrograph for the E-ELT PI: Niranjan Thatte IS: Matthias Tecza Phase A study: High-z science team: AV, Matt Jarvis, Mark Swinbank & Santiago Arribas Impact of the "first galaxies" on the high-z IGM Ly-alpha kinematics Outflows/Winds, enrichment … Spec Res: <75km/s (R=4000), 15km/s (R=20000) Spatial Res: diffraction limit - 50mas - 70pc-400pc FoV: 5"-10" - 5kpc-50kpc 95kpc Lya-Blob @ z=2.83 Smith & Jarvis 2007 See Dan's poster With an IFU data we should be able to achieve spatial and spectral resolution to test and constrain models of the highest-redshift galaxies (cf Monday's talks) Lensed L* LBG @ z=4.88 11.9kpc x 2.4kpc Swinbank et al. 07 Aprajita Verma - LAE08 Heidelberg 10/08

19. Douglas et al. in prep Douglas PhD thesis Verma et al. 2007 MNRAS 377 1024 Luminous LBGs@z~5 • Young (<100Myr), compact (1kpc), and rapidly forming stars (~few-several 10s M yr-1) in intense bursts • MSED ~ few x 109M (~10x<Mz=3, ~1.5% of the SMD(z)) • Galaxies undergoing their first generations of large-scale star formation • Driving winds and enriching the IGM with metals • May have inefficient metal mixing intra- and inter-galactic scales  pockets of Population III star-formation? • High mass surface densities (µ~6x108Mkpc-2) and core phase space densities (10-6 Mpc-3km-3s3) – similar to that of bulges and spheroids in typical present-day L* galaxies • Ly-a emitting LBGs are redder than break-only LBGs, and are potentially better tracers of large-scale structure • Mark out spatial regions in which to search for the bulk of UV-dark gas & star-formation at these redshifts with future facilities (ALMA, JWST…) All hallmarks of the early evolution of massive galaxies Aprajita Verma - LAE08 Heidelberg 10/08