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New tales of molecular gas in galaxies: (not so) near
and far
Jeff Wagg
Max-Planck/NRAO Fellow
NRAO – Socorro
NRAO postdoc symposium
Socorro
April 29, 2009
“Solid science, but there are enough high-z CO detections
now that the prospect of adding a few more is not
overly exciting”
Comment from GBT referee, April 2007
CO line emission as a tracer of molecular gas at high-redshift: fueling
star-formation and AGN activity
Obscured star-formation rate
Riechers et al. 2006
Molecular gas mass
MH2 ~ 0.8 LCO [Msun] ULIRGS (Downes & Solomon 1998)
MH2 ~ 4.6 L CO [Msun] Milky Way (e.g. Solomon & Barrett 1991)
CO line emission as a tracer of molecular gas: fueling star-formation and
AGN activity
Weiss et al. 2005
●CO molecule exhibits rotational transitions between quantum numbers Jupper -> Jlower
at frequency spacings: Jupper × 115 GHz
●CO emission line “spectral energy distribution” of a galaxy indicates density and
temperature of gas
Low excitation molecular gas in “normal” galaxies at z~1.5
Daddi et al. 2008
CO J=1-0 - GBT/Q-band, 12hrs
on
(Aravena, Wagg, Carilli ea in prep.)
●BzK galaxies: star-forming galaxies
identified in (B-z) vs. (z-K) diagram (Daddi
et al. 2004)
●CO J=2-1 with PdBI: large masses of
Dannerbauer et al. in prep molecular gas (1010 Msun) forming stars with
low efficiency (~100 Msun/yr)
Outline
• molecular gas in ULIRG-to-QSO transition objects at z ~ 0.3
• measuring redshifts for submm galaxies: water megamasers?
• molecular gas and the epoch of reionization
Molecular gas in ULIRG-to-QSO transition objects
1. ultraluminous infrared galaxy (ULIRG): merger of two gas-rich galaxies
2. AGN and starburst evolve coevally within ULIRG
3. optically luminous QSO emerges after dust is shed
Molecular gas in ULIRG-to-QSO transition objects
1. ultraluminous infrared galaxy (ULIRG): merger of two gas-rich galaxies
2. AGN and starburst evolve coevally within ULIRG
3. optically luminous QSO emerges after dust is shed
IRAS 00275-2859
Lipari et al 1994; Canalizo & Stockton 2001
Molecular gas in ULIRG-to-QSO transition objects
CO emission in luminous QSOs at low Optical/HST: most luminous
redshift QSOs are early-type
Alloin et al 1992, Haas et al 2000, Evans et al Dunlop et al 2003, Floyd et al 2004
2001, Scoville et al 2003, Bertram et al 2007
Molecular gas in a “Naked” QSO: HE0450-2958 at z=0.286
Papadopoulos, Feain, Wagg & Wilner 2008
Contours: CO J=1-0 (ATCA)
Greyscale: HST • AGN with no apparent host galaxy
cross - optical quasar (Magain et al 2005)
star: ULIRG
• strong IRAS source: SFR~370 Msun/yr
(de Grijp et al 1987)
• ATCA and SMA CO imaging reveal cold gas:
MH2 ~(1-2)×1010 Msun
R32 < 0.39 (R32~0.65 for ULIRGs)
• gas feeding both AGN and starburst?
Single-dish JCMT spectra and future work
Wagg, Papadopoulos, Ivison & Aravena
CO J=4-3 spectra - JCMT/Harp-B
• broad CO J=4-3 lines: ~1000km/s
• tentative detection of CO J=1-0 in
1821+643 at z=0.287 with CARMA
CO J=1-0 CARMA (15 hrs)
• combination of PdBI, CARMA,
ALMA will isolate molecular gas in
ULIRG->QSO transition objects
HST imaging Floyd et al 2004
Using molecular emission lines to measure redshifts for
massive, high-redshift ULIRGs
850um Hubble Deep Field
Hughes et al. 1998
Chapman et al. 2005 GBT K-band
Wagg et al 2007
GN20 CO J=4-3
Pope et al 2005 Daddi et al. 2009
HDF850.5
Wang et al 2007
CO J=4-3? PdBI
Daddi et al. 2009
H2O megamasers at high-redshift I: detection in lensed quasars
• H2O masers at 22.235 GHz arise in sites
of star-formation or AGN activity
(see Lo 2005 for review)
• tentative correlation between H2O line
luminosity and FIR luminosity in nearby
FIR bright galaxies (Castangia et al 2008)
Castangia et al 2008
H2O megamaser at z=2.64
EVLA/Effelsberg Impellizzeri et al 2008
H2O megamasers at high-redshift II: EVLA searches in lensed starbursts
• Edmonds, Wagg et al. 2009
CO J=3-2 – PdBI Kneib et al 2005
• Wagg & Momjian, AJ, submitted
• FIR luminosity in submm galaxies mainly powered
by star-formation (e.g. Alexander et al 2005)
• H2O “kilomasers” found in nearby star-forming
galaxies (e.g. Henkel et al. 2005)
• SMMJ16359: LH2O < 1890 Msun (dV = 80 km/s)
EVLA C-band spectra
Molecular gas in galaxies during reionization I: CO in z > 5.7 quasars
IRAM PdBI
Ran Wang et al. in prep.
IRAM PdBI
6 x 15m antennas
• LFIR~ 1e13 Lo French Alps
• Mgas ~ 2e10 Mo 1 – 3 mm
• Mdust ~ 4e8 Mo
Molecular gas in galaxies during reionization II: CO in Ly emitters
Wagg, Kanekar & Carilli 2009
HCM 6A IOK-1
z=6.56 Hu et al 2002 z=6.96 Iye et al 2006
• LAEs: `normal’ star-forming
galaxies responsible for reionization
• stellar masses: 108 – 10 Msun
• SFRs: 3 – 140 Msun/yr
• dusty? (Chary et al. 2005;
Finkelstein et al 2009)
CO J=1-0 GBT Ku-band
• No CO J=1-0 detected with GBT - HCM6A: L’CO < 6.1E+9 (dV/300)1/2 K km/s pc2
MH2 < 4.9E+9 (dV/300)1/2 (XCO/0.8) Msun
• First sensitive constraints on the presence of molecular gas in LAEs
Summary
• molecular gas in ULIRG-to-QSO transition objects at z ~ 0.3
• interferometric imaging of CO line emission reveals
evidence for wet-dry mergers at z~0.3
• broad CO lines detected in quasar host galaxies
• measuring redshifts for submm galaxies: water megamasers?
• megamasers not detected in strongly lensed, starburst
galaxies at z~2.5
• broadband CO emission line searches likely the best
means of measuring redshifts for submm galaxies
• molecular gas and the epoch of cosmic reionization
• total number of quasars detected in high-J CO line
emission at z > 5.7: eight
• sensitive searches for CO line emisison in z>6.5 LAEs
suggest small quantities of molecular gas
Acknowledgements
Thank you!!
Chris Carilli, the Max-Planck Society and the Humboldt Foundation
Dale, Miller and the NRAO
NRAO collaborators: Nissim, Frazer, Emmanuel, Ron, D.J. , Paul and Manuel
Students: Michael Carilli, Robert Edmonds and Ran Wang
AOC staff and fellow postdocs
Molecular gas in the radio quiet quasar: 1821+643 at z=0.297
Wagg, Papadopoulos & Ivison in prep.
• 1821+643: radio-quiet quasar
• extreme FIR luminosity ???
• CO associated with nearby, interacting
galaxy, not elliptical
Floyd et al. 2004
CO J=1-0 CARMA (15 hrs)
