Why do we need a vlst for studying qso absorption lines
This presentation is the property of its rightful owner.
Sponsored Links
1 / 35

Why do we need a VLST for studying QSO absorption lines? PowerPoint PPT Presentation


  • 55 Views
  • Uploaded on
  • Presentation posted in: General

Why do we need a VLST for studying QSO absorption lines?. So that we can go deeper…. Brilliant!. A Genius!!. sublime…. The Critics agree…. QSO absorption lines and a VLST. My top-three topics for QAL studies in the UV: {detailed probing of the `cosmic web’ (Ly a , weak metal lines)} 

Download Presentation

Why do we need a VLST for studying QSO absorption lines?

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Why do we need a vlst for studying qso absorption lines

Why do we need a VLST for studying QSO absorption lines?

So that

we can

go deeper…


Why do we need a vlst for studying qso absorption lines

Brilliant!

A Genius!!

sublime….

The Critics agree….


Qso absorption lines and a vlst

QSO absorption lines and a VLST

My top-three topics for QAL studies in the UV:

{detailed probing of the `cosmic web’ (Lya, weak metal lines)} 

metallicity of nearby galaxies

QSO absorption lines from QSOs (briefly)


What about metallicity

What about metallicity?

  • Measurements from QSO absorption lines show little evolution from z=4 to ~1

  • The lack of evolution appears to be largely independent of column density

    • from Lya-forest clouds to Damped Lya systems (DLAs)


What about metallicity1

13.5-5.8 Gyr

5.8 – 1.2 Gyr

Pettini (2003)

What about metallicity?

Kinda surprising…. expect `gas’ in the universe to be getting more enriched with time as galaxies evolve and pollute

  • DLAs in particular don’t approach solar at z=0


Why do we need a vlst for studying qso absorption lines

Let’s measure metallicities from nearby galaxies…

  • Advantages of looking at nearby galaxies:

  • determine wide range of galaxy properties (21cm, X-ray, etc.)

  • select low luminosity galaxies that are hard to see at higher-z

  • check for fainter interlopers close to any selected galaxy

  • easier to examine the galaxy’s environment (isolated, group, cluster)


Why do we need a vlst for studying qso absorption lines

NGC 4319, v=1405 km s-1

QSO absorption lines from nearby galaxies

Mrk 205, z=0.071


Time for one example to show what can be done and how far we ve got

Time for one example…… to show what can be done and how far we’ve got

Used HST + STIS to measure abundances towards

HS1543+5921 / SBS1543+593

With:

Ed Jenkins,

Todd Tripp,

Max Pettini


Why do we need a vlst for studying qso absorption lines

10’

DSS image

SBS1543+593

HS 1543+5921

z=0.807


Why do we need a vlst for studying qso absorption lines

QSO

star

HII region,

z=0.009

(2700 km s-1)

APO 3.5m, R, 15 min

Reimers

& Hagen 98


Why do we need a vlst for studying qso absorption lines

QSO

star

HST STIS (clear), 800s


Spectroscopy

Spectroscopy

F(1200) = 2.6x10-15 pretty hard even with first-order gratings; fortunately CVZ object (15 orbits)

[S/H] = -0.4

Higher than

expected?


Why do we need a vlst for studying qso absorption lines

HS1543+5921

PG1543+489

Pettini (2003)

Compare Zs with DLA samples


List of other suitable pairs which can be observed at high spectral resolution with hst

List of other suitable pairs which can be observed at high spectral resolution with HST:


What could we do with a vlst

What could we do with a VLST?

  • There are plenty of QSO-galaxy pairs in the sky! Just too faint!

  • Go deeper, the number of interesting pairs becomes substantial


Why do we need a vlst for studying qso absorption lines

STIS echelle


What could we do with a vlst1

What could we do with a VLST?

  • There are plenty of QSO-galaxy pairs in the sky! Just too faint!

  • Go deeper, the number of interesting pairs becomes substantial

  • Already know some QSO intercept large N(H I) from 21cm maps [knowing HI a priori helps choose a target to measure Z]

  • Four examples, just to show what we’re missing out on….

    • VLA maps from Womble (1993)

    • optical images from DSS


Why do we need a vlst for studying qso absorption lines

Gal: IC1746

cz = 5201 km/s

QSO: 0151+045

sep = 10 kpc

V=14.8?

F(1220)=3e-15

==30 STIS orbits

Nice edge-on galaxy probe outer disk


Why do we need a vlst for studying qso absorption lines

N(H I) ~ 7-13 e19 cm/2

CaII: 


Why do we need a vlst for studying qso absorption lines

Gal: NGC3184

cz = 592 km/s

QSO: 1015+416

sep = 11 kpc

V=17.7 – 19.1?

F(1220)=?

chance to probe edge of huge HI envelope…

…compare to metallicties from HII regions…


Why do we need a vlst for studying qso absorption lines

N(H I) ~ 4e19 cm/2

CaII: 


Why do we need a vlst for studying qso absorption lines

Gal: NGC470

cz = 2374 km/s

QSO: Q0117+031

sep = 10 kpc

V=18.2

F(1220)=?

NGC 474

19.9


Why do we need a vlst for studying qso absorption lines

N(H I) ~ 6-10 e20 cm/2

CaII: 


Why do we need a vlst for studying qso absorption lines

Gal: NGC3079

cz = 1125 km/s

QSO: Q0957+558

sep = 8 kpc

V=17.4

F(1220)=1e-15


Why do we need a vlst for studying qso absorption lines

2.5 hrs, F658N, WFPC2

Great way to study outflows!


Why do we need a vlst for studying qso absorption lines

N(H I) ~ 3 e20 cm/2

CaII: 


Or multiple qsos

…or multiple QSOs!

NGC 3628

(cz=843 km/s)

QSOs have ‘O’ mags between 18.7 and 20.7

4 X-ray sources

near M65

Arp et al 2002


Why do we need a vlst for studying qso absorption lines

…or multiple multiple QSOs!

(narrow metal lines

instead of DLAs)


Summary

Summary

  • There are plenty of QSO-galaxy pairs known:

    • though number with 21cm maps and/or CaII/NaI observations is smaller

    • more behind galaxy disks to appear with GALEX presumably

    • … and using SDSS photo-z techniques

  • Need UV telescope that can:

    • reach 10 km/s resolution down to 20 mag

      • factor of 250 in flux over STIS G140M echelle

    • large wavelength range to cover many lines

      • important for ionization corrections

      • …. and for studying relative abundunace patterns which can be used to infer history of metal production

    • how about…. a LiF coated mirror and do < 1100A as well? i.e. HST+FUSE

  • Payoff:

    • detailed inventory of galaxy metallicities in the local universe

    • for individual galaxies:

      • ability to compare ISM abundances with values from HII regions

      • variations of metallicities as a function of radius if multiple sightlines available

      • kinematics and ionization structure of gas in the outer regions of galaxies

    • probes of the interface between a galaxy and the IGM


Qso absorption lines from qsos

QSO absorption lines from QSOs

Suppose instead of probing galaxies, could probe QSOs instead.

  • QSOs are ejecting large amounts of metal-enriched gas into the IGM  might expect:

    • metallicity of the gas around a QSO to be high

    • ionization of the gas to be high

    • absorption to be complex from outflows mixing with the IGM

  • By observing many QSO-QSO pairs, should be able to track the enrichment of the IGM with radius

  • Compare absorption from a f/g QSO with associated absorption (zabs ~ zem) in the QSO’s spectrum

    • learn more about associated systems, compare structure, ionization, and metallicity variations over small scales.


Available qso qso pairs

Available QSO-QSO pairs

  • SDSS provides a large # of QSO pair candidates with the b/g QSO < 20th

  • Often require follow-up spectra of one of the pairs from the ground

    • both from collaborators: Joe Hannawi, Gordon Richards and Michael Strauss


J0836 4841

4.1”,

19 h-1 kpc

J0836+4841

z=0.66

z=1.71


J0836 48411

J0836+4841

  • zabs = zQSO = 0.66 in SDSS spec

  • Likely to be a DLA!

  • Probably host galaxy

  • Perhaps high metallicity?


J2313 1445

3e-16

J2313+1445

zbg = 1.52

zfg = 0.79

sep = 6.4” or

32 h-1 kpc

  • - outflowing gas from jet

  • companion fuelling QSO

  • unrelated galaxy in

  • QSO cluster


A future project

A future project

  • QSOs appear to cause the same kinds of MgII systems that field galaxies cause

  • Will need a VLST to do the kinds of spectroscopy of interest….


  • Login