Dust and Molecules at high-z R. Srianand, IUCAA, PUNE C OLLABORATORS - - PowerPoint PPT Presentation

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Dust and Molecules at high-z R. Srianand, IUCAA, PUNE C OLLABORATORS - - PowerPoint PPT Presentation

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Dust and Molecules at high-z R. Srianand, IUCAA, PUNE C OLLABORATORS : Patrick Petitjean, IAP , France Neeraj Gupta, ASTRON, Netherlands Pasquier Noterdaeme, IAP , France Cedric Ledoux, ESO, Chile Sebastian Lopez,Universidad

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Dust and Molecules at high-z

  • R. Srianand, IUCAA, PUNE
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COLLABORATORS:

  • Patrick Petitjean, IAP

, France

  • Neeraj Gupta, ASTRON, Netherlands
  • Pasquier Noterdaeme, IAP

, France

  • Cedric Ledoux, ESO, Chile
  • Sebastian Lopez,Universidad de Chile, Chile
  • Hadi Rahmani, IUCAA
  • Sowgat Muzahid, IUCAA
  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 1

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PLAN OF THE TALK:

  • Basic introduction to damped Lyman-α systems (DLAs)
  • Search in DLAs for

– H2 and HD absorption – CO molecule – 2175 ˚ A bump – DIBs

  • Summary
  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 2

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QSO SPECTRUM: ABSORPTION LINES

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 3

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1 2 3 4 5 z 0.0 0.5 1.0 1.5 Ωg

DLA (× 10 −3)

2 4 6 7 8 9 10 11 12 lookback time (Gyr)

DLAS CONTAIN GOOD AMOUNT OF Ωg:

Noterdaeme et al. 2009, A&A, 505, 1087

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 4

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WIDE RANGE OF HEAVY ELEMENTS

  • R. Srianand, IUCAA, PUNE

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PROPERTIES OF DLAS: HIGH Z DLAS AND LBGS

Most of these have high metallicity absorbers−Moller et al., 2002

  • R. Srianand, IUCAA, PUNE

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1200 1205 1210 1215 1220 1225 1230 Rest Wavelength (Å) 5 10 15 20 25 Fλ (10−17 erg s−1 cm−2Å−1) SiIII weighted mean

1213.2 1214.8 1216.5 1218.2 −0.5 0.0 0.5 1.0 0.0 0.4 0.8 1.2

CIIλ1334

0.0 0.2 0.4 0.6 0.8 1.0 log(1+z) 0.01 0.10 ρ*( MO

  • yr -1 Mpc -3 )

.

INSITU STAR-FORMATION IN HIGH-Z DLAS

Rahmani et al. 2010

  • R. Srianand, IUCAA, PUNE

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PHOTO-DISSOCIATION REGIONS:

  • R. Srianand, IUCAA, PUNE

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H2 MOLECULES:

  • R. Srianand, IUCAA, PUNE

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H2 AND C I IN DLAS:

  • R. Srianand, IUCAA, PUNE

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SEARCH FOR H2 IN DLAS: UVES SURVEY

Petitjean et al. 2000; Ledoux et al. 2003; Srianand et al. 2005; Noterdaeme et al. 2008 & Srianand et al. 2011

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 11

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MOTIVATION: UVES SURVEY

  • Quantify the H2 fraction in DLAs
  • Use the rotational level population to infer the physical state of the gas
  • Establish the connection between C I and H2 and get additional constraints on

physical state of the gas.

  • Constraining the variation of fundamental constants.
  • Probing the thermal evolution of CMBR.
  • Obtaining HD/H2 and providing independent constraints on Ωb
  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 12

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RESULTS OF OUR UVES SURVEY:

  • Out of 77 DLAs at z≥1.8 only 13 show H2 detection.
  • Molecular fraction: 5 × 10−7 and 0.1. (Diffuse gas!).
  • Molecular fraction: ≤ 10−5 in non-detections
  • H2 detection is independent of H I column density
  • H2 detection is more frequent in high metallicity and dusty DLAs.
  • T = 100-300 K, nH = 10 − 200 cm−3 and G = few G0.
  • Good candidates for constraining ∆µ/µ.
  • HD is detected in one case. D/H is consistent with WMAP constraints.
  • Photoionization models: most of the DLAs originate from low density hot gas.
  • 21-cm survey: The H2 gas contains very small amount of N(H I). The extent of

this component is less than 10 pc.

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 13

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SEARCH FOR CO IN DLAS:

  • To detect translucent and molecular gas.
  • Automatic search for very strong C I absorption in the SDSS

spectrum of QSOs. 45 strong systems found.

  • The expected CO bands are in high wavelength side of the

Lyman-α emission from the QSOs so one can search for them at z ≥ 1.5.

  • Detection of CO at z ≥ 2 will allow one to measure CO/H2 directly

at different environments.

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 14

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FIRST DETECTION OF CO IN A DLA AT HIGH-Z

  • R. Srianand, IUCAA, PUNE

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VOIGT PROFILE FITTING OF DIFFERENT J LEVELS:

  • R. Srianand, IUCAA, PUNE

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CO EXCITATION DIAGRAM

  • R. Srianand, IUCAA, PUNE

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0.0 0.2 0.4 0.6 0.8 1.0 fH2 0.01 0.1 1.0 10 100 N(CO)/N(C0)

Translucent Diffuse

0.0 0.2 0.4 0.6 0.8 1.0 fH2 10−8 10−7 10−6 10−5 10−4 N(CO)/N(H2)

Translucent Diffuse

CO/H2 RATIO

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 18

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0.0 0.5 1.0 1.5 2.0 2.5 3.0 z 2 4 6 8 10 12 14 TCMB (K)

TCMB

0 (1+z)

TCMB

0 (1+z) (1−β)

  • TCMB(z) = (2.725 ± 0.002) × (1 + z)1−β

with β = −0.007 ± 0.027.

  • Following decaying dark energy models of Jetzer

et al. 2010, TCMB(z) = TCMB(z = 0) × (1 + z)3γ−1  (m − 3Ωm) + x(1 + z)m−3(Ωm − 1) (m − 3)Ωm   γ Where, γ = 4/3, Ωm = 0.275 ± 0.015 and m=3(weff + 1) with weff = p/ρ. The best fitted value is weff = −0.996 ± 0.025.

T(CMBR) VS. Z

Noterdaeme et al. 2011, A&AL, 526, L7

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 19

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CO SURVEY: STATUS

  • 16 bright candidates were observed with UVES and about 20 is being observed

with X-SHOOTER.

  • Till now there are 7 CO detections. Whenever z≥ 2 we are detecting very

strong H2 and HD molecules.

  • Typical detection limit of N(CO) is few times 1013 cm−2.
  • 50% of the data yet to be analysed.
  • CO detections are all towards red objects not in SDSS because of color

selection but for other reasons.

  • Strong C I absorbers allow us to probe the translucent gas at high-z.
  • X-SHOOTER spectra also allow us to search for associated emission from the

absorbers. Srianand et al. 2008; Noterdaeme et al., 2009; 2010; 2011

  • R. Srianand, IUCAA, PUNE

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2175 ˚ A FEATURES:

  • R. Srianand, IUCAA, PUNE

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QSO COMPOSITE SPECTRUM:

  • R. Srianand, IUCAA, PUNE

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2170 ˚ A DUST FEATURE TOWARDS J0850+5159

  • R. Srianand, IUCAA, PUNE

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SIGNIFICANCE OF THE FEATURE:

  • R. Srianand, IUCAA, PUNE

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2170 ˚ A DUST FEATURE TOWARDS J0852+3432

  • R. Srianand, IUCAA, PUNE

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SIGNIFICANCE OF THE FEATURE:

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 26

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GMRT SPECTRA:

  • R. Srianand, IUCAA, PUNE

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SED FITTING: RESULTS

  • For J0850+5159 :

– N(H I) = (5.73±1.10)×1021 cm−2 – Ts ∼ 190+124

−69 K

  • For J0852+3435 :

– N(H I) = 6.97±1.30 × 1021 cm−2 – Ts/fc = 536+234

−88 K.

  • R. Srianand, IUCAA, PUNE

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CO AND UV BUMP

  • R. Srianand, IUCAA, PUNE

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SDSS SAMPLE:

  • 9.7 µm silicate feature is seen in the systems that show UV bump.

(Kulkarni et al. 2011, ApJ, 726, 14)

  • ∼ 15 UV bump candidates. Most of them will be searched for CO

using VLT.

  • 39 Mg II systems with bump are reported by Jiang et al. 2011,

ApJ, 732, 110.

  • Estimation of redshift path length for dusty absorbers.
  • R. Srianand, IUCAA, PUNE

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DIBS AT HIGH-Z:

  • R. Srianand, IUCAA, PUNE

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400 600 800 1000 1200 1400 1600

  • Obs. wavelength (nm)

5 10 15 20 25 30 Fλ (10−17 erg s−1 cm−2Å−1) QSO composite J1135−0010 QSO composite, AV=0.11

DIBS IN DLAS: X-SHOOTER SPECTRA

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 32

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SLIDE 34 1290 1300 1310 1320 DECLINATION (J2000) RIGHT ASCENSION (J2000) 08 21 55.5 55.0 54.5 54.0 53.5 53.0 52.5 52.0 50 31 35 30 25 20 15 10 1160 1180 1200 1220 1240 1260 1280 DECLINATION (J2000) RIGHT ASCENSION (J2000) 08 50 00.0 49 59.5 59.0 58.5 58.0 57.5 57.0 56.5 56.0 55.5 51 08 50 45 40 35 30 25 20 15 1150 1200 1250 DECLINATION (J2000) RIGHT ASCENSION (J2000) 12 28 49.0 48.5 48.0 47.5 47.0 46.5 37 06 25 20 15 10 05 00 05 55

1120 1140 1160 1180 1200 DECLINATION (J2000) RIGHT ASCENSION (J2000) 12 42 00 41 59 58 57 56 55 54 63 32 46 44 42 40 38 36 34 32

1160 1180 1200 1220 DECLINATION (J2000) RIGHT ASCENSION (J2000) 11 10 28 27 26 25 24 23 22 21 03 21 55 50 45 40 35 30 25 20 15

QSO-GALAXY PAIRS: GMRT MINI-SURVEY

Gupta et al. 2010

  • R. Srianand, IUCAA, PUNE

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QSO-GALAXY PAIRS: J124157.54+633241.6

  • R. Srianand, IUCAA, PUNE

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0.5 1 1.5 10 20 30 0.5 1 1.5 10 20 30

QSO-GALAXY PAIRS: DIBS

  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 35

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SUMMARY:

  • We are successful in detecting the basic molecules in DLAs under

normal interstellar medium conditions.

  • Complex molecules are still elusive. May be due to colour

selection of QSOs. New selection is needed.

  • 2175 ˚

A feature is detected at high-z. DIBs are still elusive for z ≥ 0.5.

  • Blind radio survey will be helpful.
  • R. Srianand, IUCAA, PUNE

Dust Meeting-2011 36