How Big. Are IGM Absorbers? What? Charles Danforth U. Colorado. John Stocke Mike Shull Brian Keeney Devin Silvia etc.

Transcription

1 How Big What? Are IGM Absorbers? Charles Danforth U. Colorado John Stocke Mike Shull Brian Keeney Devin Silvia etc. The Leiden Summer CGM-Galaxy Interface Workshop 20/6/13

2 The cartoon picture of the Lyα forest There is no IGM! It s all CGM!*

3 Plenty of evidence that IGM, particularly metal absorbers, is associated with galaxies HI HI+metals Stocke et al. 2012

4 Tumlinson et al. (2011) O VI probes of galactic halos and CGM Strong O VI absorbers in CGM around star-forming galaxies

5 Many IGM systems are not associated with galaxies Strong Absorbers IGM Weak Absorbers CGM 45 QSO-galaxy pairs (13 targeted, 32 serendipitous) Stocke, Keeney, Danforth, Penton, Shull 2012

6 What is actually known? redshift N = n dl temperature (maybe) metallicity (maybe) galaxy relationship (sometimes, maybe)

7 DM halo! AGN feedback! IGM absorber large-scale structure! all a big conspiracy, man! cooling flow! filament! getting our stories straight is critical

8 Transverse absorber correlations to the rescue! correlation between absorbers in adjacent sight lines cloud sizes physical density association with galaxies,and/or LSS

9 The usual method mostly at z>1 Weymann & Foltz 1983 Foltz Crotts 1994, Smette 1992, 95 Dinshaw+ 1997, 98, Lopez Rosenberg etc.

10 ...has limitations pairs of background sources are rare typical cloud size turns out to be ~sight line spacing galaxy information difficult (requires many milli-steidels of Keck time)

11 Can we use all this COS spectroscopy to say something about IGM absorber scales? low-redshift close pairs not needed galaxy information is easier! UV sources (rare)

12 COS IGM Survey: Scope 4 years of COS science observations >300 AGN sight lines observed general-purpose database of low-z IGM absorbers baryon census, evolution, galaxy-igm relationship, etc. moderate/weak IGM absorbers only care about the good data. ~70 sight lines, Δz(Lyα)>22, Δz(OVI)>15 (Danforth , in prep) Matt Stevans UT Austin

13 COS IGM Survey: Results 70 sight lines 5391 IGM lines (z<1) 2591 IGM systems all kinds of cool low-z cosmology results!

14 Absorber pairs Paired Absorbers Rudie+12 z 2

15 Two Point Correlation Function ξ( v) N obs( v) N rand ( v) 1 galaxy-galaxy TPCF

16 Multiple probes of individual objects? Keeney+ 2013

17 COS multiples sample AGN Pairs+ separation Δzcommon Program RXJ / HE / HE ES / 1SAXJ TonS210 / B / B C273 / Q ~ / 0.42 GTO GTO ~ Chris Thom GTO LBQS pair 1.29 >0.9! Neil Creighton

18 paired COS sight lines Lyα sensitivity gaps 0.1L* 3C273/Q L* 1.0L* TonS210/B0117 Triple Probe 1SJ1032/1ES1028 filament cluster/group LBQS A/B halo

19 9.4 Correlations seen over small transverse distances R vir 250 kpc (L/L ) 0.2ish

20 similar absorption seen over kpc scale Keeney Keeney+ 2013

21

22 sep=250 kpc

23 sep=90 kpc

24 Correlations over large (!) distances

25 Correlations over large (!) distances

26 Lyα 1216 nearest galaxy (~4 Mpc away) 1.3 Mpc OVI 1032Å

27 Looks like a filament. 3.1 Mpc No single galaxy close in D or z

28 filament?

29 6.2 Mpc Looks more like a filament. A bit closer in Δz this time.

30 Maybe they are chance coincidences? dn/dzchance<1

31 Correlation in absorber quantities?

32 Correlation in absorber quantities?

33 Correlation in absorber quantities? Maybe at least a trend?

34 What about metal absorbers? only three pairs show metals in both sight lines, all at dperp<500 kpc seven show metals in one but not the other

35 Conclusions First Impressions Lyα TPCF lower, smaller Δv than galaxy TPCF Lyα absorber redshifts correlated over much larger transverse scales than expected. poor correlation in N, b, metallicity no examples of dperp>1 Mpc metal systems One size does not fit all.

36 Dank u wel!