scholarly journals Is atomic carbon a good tracer of molecular gas in metal-poor galaxies?

2016 ◽  
Vol 456 (4) ◽  
pp. 3596-3609 ◽  
Author(s):  
Simon C. O. Glover ◽  
Paul C. Clark
Keyword(s):  
Molecular Gas ◽  
Atomic Carbon ◽  
Good Tracer

scholarly journals Atomic carbon [C i](3P1–3P0) mapping of the nearby galaxy M 83

2021 ◽  
Author(s):  
Yusuke Miyamoto ◽  
Atsushi Yasuda ◽  
Yoshimasa Watanabe ◽  
Masumichi Seta ◽  
Nario Kuno ◽  
...  
Keyword(s):  
Galactic Disk ◽  
Abundance Ratio ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Atomic Carbon ◽  
Single Temperature ◽  
Integrated Intensity ◽  
Spectrum Distribution ◽  
Good Tracer ◽  
Ir Emission

Abstract Atomic carbon (C i) has been proposed to be a global tracer of the molecular gas as a substitute for CO, however, its utility remains unproven. To evaluate the suitability of C i as the tracer, we performed [C i](3P1–3P0) [hereinafter [C i](1–0)] mapping observations of the northern part of the nearby spiral galaxy M 83 with the Atacama Submillimeter Telescope Experiment (ASTE) telescope and compared the distributions of [C i](1–0) with CO lines [CO(1–0), CO(3–2), and 13CO(1–0)], H i, and infrared (IR) emission (70, 160, and 250 μm). The [C i](1–0) distribution in the central region is similar to that of the CO lines, whereas [C i](1–0) in the arm region is distributed outside the CO. We examined the dust temperature, Tdust, and dust mass surface density, Σdust, by fitting the IR continuum-spectrum distribution with a single-temperature modified blackbody. The distribution of Σdust shows a much better consistency with the integrated intensity of CO(1–0) than with that of [C i](1–0), indicating that CO(1–0) is a good tracer of the cold molecular gas. The spatial distribution of the [C i] excitation temperature, Tex, was examined using the intensity ratio of the two [C i] transitions. An appropriate Tex at the central, bar, arm, and inter-arm regions yields a constant [C]$/$[H2] abundance ratio of ∼7 × 10−5 within a range of 0.1 dex in all regions. We successfully detected weak [C i](1–0) emission, even in the inter-arm region, in addition to the central, arm, and bar regions, using spectral stacking analysis. The stacked intensity of [C i](1–0) is found to be strongly correlated with Tdust. Our results indicate that the atomic carbon is a photodissociation product of CO, and consequently, compared to CO(1–0), [C i](1–0) is less reliable in tracing the bulk of “cold” molecular gas in the galactic disk.

scholarly journals Planck’s Dusty GEMS

2019 ◽  
Vol 624 ◽  
pp. A23 ◽  
Author(s):  
N. P. H. Nesvadba ◽  
R. Cañameras ◽  
R. Kneissl ◽  
S. Koenig ◽  
C. Yang ◽  
...  
Keyword(s):  
High Redshift ◽  
Starburst Galaxies ◽  
Molecular Gas ◽  
Atomic Carbon ◽  
High Redshift Galaxies ◽  
Neutral Gas ◽  
The Common ◽  
The Masses ◽  
Better Than ◽  
Good Agreement

The bright 3P1–3P0 ([CI] 1–0) and 3P2–3P1 ([CI] 2–1) lines of atomic carbon are becoming more and more widely employed as tracers of the cold neutral gas in high-redshift galaxies. Here we present observations of these lines in the 11 galaxies of the set of Planck’s Dusty GEMS, the brightest gravitationally lensed galaxies on the extragalactic submillimeter sky probed by the Planck satellite. We have [CI] 1–0 and [CI] 2–1 measurements for seven and eight of these galaxies, respectively, including four galaxies where both lines have been measured. We use our observations to constrain the gas excitation mechanism, excitation temperatures, optical depths, atomic carbon and molecular gas masses, and carbon abundances. Ratios of LCI/LFIR are similar to those found in the local universe, and suggest that the total cooling budget through atomic carbon has not significantly changed in the last 12 Gyr. Both lines are optically thin and trace 1 − 6 × 107 M⊙ of atomic carbon. Carbon abundances, XCI, are between 2.5 and 4 × 10−5, for an ultra-luminous infrared galaxy (ULIRG) CO-to-H2 conversion factor of αCO = 0.8 M⊙ / [K km s−1 pc2]. Ratios of molecular gas masses derived from [CI] 1–0 and CO agree within the measurement uncertainties for five galaxies, and agree to better than a factor of two for another two with [CI] 1–0 measurements, after carefully taking CO excitation into account. This does not support the idea that intense, high-redshift starburst galaxies host large quantities of “CO-dark” gas. These results support the common assumptions underlying most molecular gas mass estimates made for massive, dusty, high-redshift starburst galaxies, although the good agreement between the masses obtained with both tracers cannot be taken as independent confirmation of either αCO or XCI.

scholarly journals Extreme conditions in the molecular gas of lensed star-forming galaxies at z ~3

2018 ◽  
Vol 615 ◽  
pp. A142 ◽  
Author(s):  
Paola Andreani ◽  
Edwin Retana-Montenegro ◽  
Zhi-Yu Zhang ◽  
Padelis Papadopoulos ◽  
Chentao Yang ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
High Redshift ◽  
Molecular Gas ◽  
Extreme Conditions ◽  
Atomic Carbon ◽  
Power Sources ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Nearby Galaxies

Context. Atomic carbon can be an efficient tracer of the molecular gas mass, and when combined to the detection of high-J and low-J CO lines it yields also a sensitive probe of the power sources in the molecular gas of high-redshift galaxies. Aims. The recently installed SEPIA 5 receiver at the focus of the APEX telescope has opened up a new window at frequencies 159–211 GHz allowing the exploration of the atomic carbon in high-z galaxies, at previously inaccessible frequencies from the ground. We have targeted three gravitationally lensed galaxies at redshift of about 3 and conducted a comparative study of the observed high-J CO/CI ratios with well-studied nearby galaxies. Methods. Atomic carbon (CI(2–1)) was detected in one of the three targets and marginally in a second, while in all three targets the J = 7→6 CO line is detected. Results. The CO(7–6)/CI(2–1), CO(7–6)/CO(1–0) line ratios and the CO(7–6)/(far-IR continuum) luminosity ratio are compared to those of nearby objects. A large excitation status in the ISM of these high-z objects is seen, unless differential lensing unevenly boosts the CO line fluxes from the warm and dense gas more than the CO(1–0), CI(2–1), tracing a more widely distributed cold gas phase. We provide estimates of total molecular gas masses derived from the atomic carbon and the carbon monoxide CO(1–0), which within the uncertainties turn out to be equal.

scholarly journals Atomic carbon as a powerful tracer of molecular gas in the high-redshift Universe: perspectives for ALMA

2014 ◽  
Vol 445 (1) ◽  
pp. L124-L128 ◽  
Author(s):  
M. Tomassetti ◽  
C. Porciani ◽  
E. Romano-Díaz ◽  
A. D. Ludlow ◽  
P. P. Papadopoulos
Keyword(s):  
High Redshift ◽  
Molecular Gas ◽  
Atomic Carbon ◽  
High Redshift Universe

scholarly journals Dense Molecular Gas at High Redshift: First Detection of Emission from HCO+

2006 ◽  
Vol 2 (S235) ◽  
pp. 424-424
Author(s):  
D.A. Riechers ◽  
F. Walter ◽  
C.L. Carilli ◽  
A. Weiss ◽  
F. Bertoldi ◽  
...  
Keyword(s):  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
High Redshift ◽  
Far Infrared ◽  
Hydrogen Gas ◽  
Molecular Gas ◽  
Gas Emission ◽  
Very Large Array ◽  
Star Forming ◽  
Good Tracer

AbstractUsing the Very Large Array (VLA), we have detected the HCO+(1–0) emission line towards the Cloverleaf quasar (z = 2.56; Riechers et al. 2006). This is the first detection of ionized molecular gas emission at high redshift (z>2). HCO+ emission is a star formation indicator similar to HCN, tracing dense molecular hydrogen gas within star-forming molecular clouds. We find a HCO+/CO luminosity ratio of 0.08 and a HCO+/HCN luminosity ratio of 0.8 for the Cloverleaf. These ratios fall within the scatter of the same relationships found for low–z star–forming galaxies. However, a HCO+/HCN luminosity ratio close to unity would not be expected for the Cloverleaf if the recently suggested relation between this ratio and the far–infrared luminosity (Graciá–Carpio et al. 2006) were to hold. We conclude that a ratio between HCO+ and HCN luminosity close to 1 is likely due to the fact that the emission from both lines is optically thick and thermalized and emerges from dense regions of similar volumes. We conclude that HCO+ is potentially a good tracer for dense molecular gas at high redshift.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

Kinetics of a nonequilibrium molecular gas

1988 ◽  
Vol 155 (7) ◽  
pp. 545-545
Author(s):  
Boris M. Smirnov
Keyword(s):  
Molecular Gas ◽  
Kinetics Of

Morphology and Energetics of the Molecular Gas within a Core and a Diffuse Region in the Filamentary Dark Cloud GF 9

2000 ◽  
Vol 120 (1) ◽  
pp. 393-406 ◽  
Author(s):  
David R. Ciardi ◽  
Charles E. Woodward ◽  
Dan P. Clemens ◽  
David E. Harker ◽  
Richard J. Rudy
Keyword(s):  
Molecular Gas ◽  
Dark Cloud ◽  
Diffuse Region

High‐Resolution13CO and C18OJ= 1–0 Observations of NGC 1068: Molecular Gas Properties and a High C18O/13CO Intensity Ratio

1997 ◽  
Vol 477 (1) ◽  
pp. 518-518 ◽  
Author(s):  
Padeli P. Papadopoulos ◽  
E. R. Seaquist ◽  
N. Z. Scoville
Keyword(s):  
Intensity Ratio ◽  
Molecular Gas ◽  
Ngc 1068 ◽  
Gas Properties

The State of the Molecular Gas in a Luminous Starburst/Seyfert 2 Galaxy: NGC 1068 Revisited

1999 ◽  
Vol 516 (1) ◽  
pp. 114-126 ◽  
Author(s):  
Padeli P. Papadopoulos ◽  
E. R. Seaquist
Keyword(s):  
The State ◽  
Molecular Gas ◽  
Ngc 1068
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