Rotating Nuclear Rings and Extreme Starbursts in Ultraluminous Galaxies

Downes, D.; Solomon, P. M.

doi:10.1086/306339

Cited by 1,293 publications

(2,234 citation statements)

References 114 publications

(179 reference statements)

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“…We derive a 3σ continuum limit of 30 µJy from the Jansky VLA observations at 37.3 GHz using a bandwidth larger than shown here. Gaussian fits to the lines give a full width at half maximum (FWHM) of 400±30 km s -1 , narrower than typically found in sub-millimeter selected galaxies 13 29 . The cross indicates the position and its 5σ uncertainty of the restframe 158 μm continuum emission peak (RA: 12h36m51.976s, DEC: 62 o 12'25.80'' in the J2000.0 system), consistent with earlier millimeter interferometric measurements 3,6 at lower resolution.…”

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confidence: 70%

“…Also, no stacked detection was achieved using different combinations of high density tracers (e.g. stacking only on HCN, HNC and HCO + , or including additional species such as CN, CCH, and HC3N) or stacking on the CO isotopomers 13 CO and C 18 O. Additional References:…”

Section: Stacking Of Fainter Lines In the Frequency Scanmentioning

confidence: 99%

“…The predicted CO(1-0) line luminosity is 4.3 x 10 10 K km s -1 pc 2 , close to the measured value for CO(2-1). Depending on the choice of α, the CO-to-H 2 conversion factor, this line luminosity implies a molecular gas mass of M H2 = 3.5 x (α/0.8) x 10 10 M sun ; here α=0.8, in units of M sun (K km s -1 pc 2 ) -1 , is the conversion factor adopted for ultra-luminous infrared galaxies (ULIRGs) 13 and thought to be applicable to sub-millimeter bright objects 14 . The implied molecular gas mass fraction is M H2 /M dyn ~ 0.25±0.08 (α/0.8); i.e.…”

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confidence: 99%

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The intense starburst HDF 850.1 in a galaxy overdensity at z ≈ 5.2 in the Hubble Deep Field

Walter

Decarli

Carilli

et al. 2012

Nature

282

348

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The Hubble Deep Field (HDF) is a region in the sky that provides one of the deepest multi-wavelength views of the distant universe and has led to the detection of thousands of galaxies seen throughout cosmic time 1 . An early map of the HDF at a wavelength of 850 microns that is sensitive to dust emission powered by star formation revealed the brightest source in the field, dubbed HDF850.1 2 . For more than a decade, this source remained elusive and, despite significant efforts, no counterpart at shorter wavelengths, and thus no redshift, size or mass, could be identified 3-7 . Here we report, using a millimeter wave molecular line scan, an unambiguous redshift determination for HDF850.1 of z=5.183. This places HDF850.1 in a galaxy overdensity at z~5.2 in the HDF, corresponding to a cosmic age of only 1.1 Gyr after the Big Bang. This redshift is significantly higher than earlier estimates 3,4,6,8 and higher than most of the >100 sub-millimeter bright galaxies identified to date. The source has a star formation rate of 850 M sun yr -1 and is spatially resolved on scales of 5 kpc, with an implied dynamical mass of ~1.3x10 11 M sun , a significant fraction of which is present in the form of molecular gas. Despite our accurate redshift and position, a counterpart arising from starlight remains elusive.We have obtained a full frequency scan of the 3 mm band towards the HDF using the IRAM Plateau de Bure Interferometer (PdBI). The observations covered the frequency range from 80-115 GHz in 10 frequency settings at uniform sensitivity and at a resolution (~2.3") that is a good match to galaxy sizes at high redshift. They resulted in the detection of two lines of Carbon Monoxide (CO), the most common tracer for molecular gas at high redshift 9 , at 93.20 GHz and 111.84 GHz at the position of HDF850.1. Identifying these lines with the J=5 and J=6 rotational transitions of CO gives a redshift for HDF850.1 of z=5.183. This redshift was then unambiguously confirmed by the PdBI detection of the 158 μm line of ionized carbon ([CII], redshifted to 307.38 GHz), one of the main cooling lines of the star-forming interstellar medium. Stacking of other molecules covered by our frequency scan that trace higher volume densities did not lead to a detection (see Supplementary Information). Subsequently, the J=2 line of CO has also been detected using the NRAO Jansky Very Large Array (Jansky VLA) at 37.29 GHz. The observed [CII] and CO spectra towards HDF850.1 are shown in Fig. 1.The beamsize of our CO observations (~2.3", 15 kpc at z=5.183) is too large to spatially resolve the molecular gas emission in HDF850.1. However the [CII] and underlying continuum observations (~1.2" x 0.8") show that the source is extended (hitherto, the interstellar medium has been spatially resolved only in extremely rare quasar host galaxies at such high redshift 10 ). A single Gaussian fit yields a deconvolved size of 0.9±0.3", or 5.7±1.9 kpc at the redshift of the source. Fig. 2 shows the maps of total [CII] emission (left) as well as the red-and blue-...

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confidence: 70%

Section: Stacking Of Fainter Lines In the Frequency Scanmentioning

confidence: 99%

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confidence: 99%

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The intense starburst HDF 850.1 in a galaxy overdensity at z ≈ 5.2 in the Hubble Deep Field

Walter

Decarli

Carilli

et al. 2012

Nature

282

348

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“…Although the BCG in PKS 0745-191 falls short of the massive starbursts found in ULIRGs, the molecular gas mass could be overestimated by a factor of a few (Solomon et al 1997;Downes & Solomon 1998). For kinematically disturbed and turbulent gas associated with outflows where the gas may be optically thin even lower X CO factors are expected (for a review see Bolatto, Wolfire & Leroy 2013).…”

Section: Molecular Gas Massmentioning

confidence: 99%

ALMA observations of cold molecular gas filaments trailing rising radio bubbles in PKS 0745−191

Russell

McNamara

Fabian

et al. 2016

Mon. Not. R. Astron. Soc.

105

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We present ALMA observations of the CO(1-0) and CO(3-2) line emission tracing filaments of cold molecular gas in the central galaxy of the cluster PKS 0745-191. The total molecular gas mass of 4.6±0.3×10 9 M , assuming a Galactic X CO factor, is divided roughly equally between three filaments each extending radially 3 − 5 kpc from the galaxy centre. The emission peak is located in the SE filament ∼ 1 arcsec (2 kpc) from the nucleus. The velocities of the molecular clouds in the filaments are low, lying within ±100 km s −1 of the galaxy's systemic velocity. Their FWHMs are less than 150 km s −1 , which is significantly below the stellar velocity dispersion. Although the molecular mass of each filament is comparable to a rich spiral galaxy, such low velocities show that the filaments are transient and the clouds would disperse on < 10 7 yr timescales unless supported, likely by the indirect effect of magnetic fields. The velocity structure is inconsistent with a merger origin or gravitational free-fall of cooling gas in this massive central galaxy. If the molecular clouds originated in gas cooling even a few kpc from their current locations their velocities would exceed those observed. Instead, the projection of the N and SE filaments underneath X-ray cavities suggests they formed in the updraft behind bubbles buoyantly rising through the cluster atmosphere. Direct uplift of the dense gas by the radio bubbles appears to require an implausibly high coupling efficiency. The filaments are coincident with low temperature X-ray gas, bright optical line emission and dust lanes indicating that the molecular gas could have formed from lifted warmer gas that cooled in situ.

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“…Moreover, the molecular interstellar medium in intense starburst environments may not be just an ensemble of warm and dense Orion-type clouds. Where the most energetic star formation takes place, the gas may also have a warm but diffuse phase 11,16 , n(H 2 ) ≤ 10 3 cm −3 , generated by the disruptive effects of intense ultraviolet radiation, supernovae and the violent dynamics associated with mergers. The CO J + 1 → J, J > 2 emission from such gas will be weak, possibly for the entire starburst if this phase is dominant.…”

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confidence: 99%

A massive reservoir of low-excitation molecular gas at high redshift

Papadopoulos

Ivison

Carilli

et al. 2001

Nature

103

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Molecular hydrogen (H 2 ) is an important component of galaxies because it fuels star formation and accretion onto active galactic nuclei (AGN), the two processes that generate the large infrared luminosities of gas-rich galaxies 1,2 .Observations of spectral-line emission from the tracer molecule carbon monoxide (CO) are used to probe the properties of this gas. But the lines that have been studied in the local Universe -mostly the lower rotational transitions of J = 1 → 0 and J = 2 → 1 -have hitherto been unobservable in highredshift galaxies. Instead, higher transitions have been used, although the densities and temperatures required to excite these higher transitions may not be reached by much of the gas. As a result, past observations may have underestimated the total amount of molecular gas by a substantial amount. Here we report the discovery of large amounts of low-excitation molecular gas around -1 -the infrared-luminous quasar, APM 08279+5255 at z = 3.91, using the two lowest excitation lines of 12 CO (J = 1 → 0 and J = 2 → 1). The maps confirm the presence of hot and dense gas near the nucleus 3 , and reveal an extended reservoir of molecular gas with low excitation that is 10 to 100 times more massive than the gas traced by higher-excitation observations. This raises the possibility that significant amounts of low-excitation molecular gas may lurk in the environments of high-redshift (z > 3) galaxies.APM 08279+5255 was discovered serendiptously during a search for Galactic halo carbon stars 4 . It comprises a strongly lensed broad absorption line quasar at z = 3.9 with a complex optical spectrum and a bolometric luminosity of ∼ 10 14 L ⊙ (where L ⊙ is the luminosity of the Sun) after correcting for lensing magnification; it displays extremely strong rest-frame far-infrared emission 5 suggestive of dust-rich gas undergoing rapid star formation. The CO(4→3) and CO(9→8) lines have been detected 3 suggesting that the molecular gas must be warm, extended on a scale of up to 1 ′′ in the image plane (only 160-270 pc in the source plane), with a mass of (1 − 6) × 10 9 M ⊙ .We have used the National Radio Astronomy Observatory's Very Large Array (VLA) to detect and image CO J=1→0 and J=2→1 emission from APM 08279+5255. Emission in the CO(1→0) line ( Fig. 1) extends over scales of ∼ 7 ′′ (∼ 30 kpc at z = 3.9 for H 0 = 75 km s −1 Mpc −1 , q 0 = 0.5), well beyond the gravitationally lensed nucleus 6 where the emission from the CO(4→3) and CO(9→8) transitions is confined 3 . Maps of CO(2→1) detect the northern part of the extended emission and show it to consist of two kinematically and spatially distinct features (Fig. 2). The continuum emission detected at -2 -23 GHz emanates from the lensed nucleus and is unresolved (≤ 0.6 ′′ ) with a flux density of 0.30 ± 0.05 mJy. At 43 GHz, no continuum emission is detected at a level of σ = 0.30 mJy, and the emission expected from the hot dust in the nucleus 5 is negligible (≤ 0.04 mJy). No appreciable dust continuum is expected underlying the extra-nuclear CO(2→1) emissi...

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Rotating Nuclear Rings and Extreme Starbursts in Ultraluminous Galaxies

Cited by 1,293 publications

References 114 publications

The intense starburst HDF 850.1 in a galaxy overdensity at z ≈ 5.2 in the Hubble Deep Field

The intense starburst HDF 850.1 in a galaxy overdensity at z ≈ 5.2 in the Hubble Deep Field

ALMA observations of cold molecular gas filaments trailing rising radio bubbles in PKS 0745−191

A massive reservoir of low-excitation molecular gas at high redshift

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