THE JAMES CLERK MAXWELL TELESCOPE NEARBY GALAXIES LEGACY SURVEY. I. STAR-FORMING MOLECULAR GAS IN VIRGO CLUSTER SPIRAL GALAXIES

AbstractMolecular gas is the raw material for star formation and is commonly traced by the carbon monoxide (CO) molecule. The atmosphere blocks all but the lowest-J transitions of CO for observatories on the ground, but the launch of the Herschel Space Observatory revealed the CO emission of nearby galaxies from J = 4−3 to J = 13−12. Herschel showed that mid- and high-J CO lines in nearby galaxies are emitted from warm gas, accounting for approximately 10% of the molecular mass, but the majority of the CO luminosity. The energy budget of this warm, highly-excited gas is a significant window into the feedback interactions among molecular gas, star formation, and galaxy evolution. Likely, mechanical heating is required to explain the excitation. Such gas has also been observed in star forming regions within our galaxy.We have examined all ~300 spectra of galaxies from the Herschel Fourier Transform Spectrometer and measured line fluxes or upper limits for the CO J = 4−3 to J = 13−12, [CI], and [NII] 205 micron lines in ~200 galaxies, taking systematic effects of the FTS into account. We will present our line fitting method, illustrate trends available so far in this large sample, and preview the full 2-component radiative transfer likelihood modeling of the CO emission using an illustrative sample of 20 galaxies, including comparisons to well-resolved galactic regions. This work is a comprehensive study of mid- and high-J CO emission among a variety of galaxy types, and can be used as a resource for future (sub)millimeter studies of galaxies with ground-based instruments.

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Nuclear molecular gas in the Virgo Cluster S0 galaxy NGC 4710

Symposium - International Astronomical Union ◽

10.1017/s0074180900123976 ◽

1993 ◽

Vol 153 ◽

pp. 439-440

Author(s):

J.M. Wrobel ◽

J.D.P. Kenney

Keyword(s):

Interstellar Medium ◽

Emission Line ◽

Optical Emission ◽

Virgo Cluster ◽

Gas Analysis ◽

Molecular Gas ◽

Star Forming ◽

The Galaxy

The CO(J=1→0) emission from NGC 4710, a star–forming S0 galaxy in the Virgo Cluster, was synthesized with spatial and velocity resolutions of 7″ and 26 km s—1, respectively. The CO shows a compact morphology and co–rotates with the galaxy's stars and nuclear optical emission line gas. Analysis of the CO distribution and kinematics indicates that the nuclear molecular gas is probably gravitationally unstable, and this may explain why the galaxy is presently forming stars. Four possible origins for the nuclear molecular gas are considered. An origin via bulge star ejecta being deposited into a residual interstellar medium is favored.

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

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732560 ◽

2018 ◽

Vol 615 ◽

pp. A142 ◽

Cited By ~ 7

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.

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The JCMT nearby galaxies legacy survey – X. Environmental effects on the molecular gas and star formation properties of spiral galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stv2958 ◽

2016 ◽

Vol 456 (4) ◽

pp. 4384-4406 ◽

Cited By ~ 21

Author(s):

Angus Mok ◽

C. D. Wilson ◽

J. Golding ◽

B. E. Warren ◽

F. P. Israel ◽

...

Keyword(s):

Star Formation ◽

Environmental Effects ◽

Spiral Galaxies ◽

Molecular Gas ◽

Nearby Galaxies

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Ionized and neutral gas in the XUV discs of nearby spiral galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314009326 ◽

2014 ◽

Vol 10 (S309) ◽

pp. 65-68

Author(s):

López-Sánchez ◽

B. S. Koribalski ◽

T. Westmeier ◽

C. Esteban

Keyword(s):

Spiral Galaxies ◽

Dwarf Galaxy ◽

Chemical Abundances ◽

Ionized Gas ◽

Galaxy Interactions ◽

Star Forming ◽

Star Forming Regions ◽

Neutral Gas ◽

The Galaxy ◽

Nearby Galaxies

AbstractWe are conducting a multiwavelength study of XUV discs in nearby, gas-rich spiral galaxies combining the available UV (GALEX) observations with H i data obtained at the ATCA as part of the Local Volume HI Survey (LVHIS) project and multi-object fibre spectroscopy obtained using the 2dF/AAOmega instrument at the 3.9m AAT. Here we present the results of the multiwavelength analysis of the galaxy pair NGC 1512/1510. The H i distribution of NGC 1512 is very extended with two pronounced spiral/tidal arms. Hundreds of independent UV-bright regions are associated with dense H i clouds in the galaxy outskirts. We confirm the detection of ionized gas in the majority of them and characterize their physical properties, chemical abundances and kinematics. Both the gas distribution andthe distribution of the star-forming regions are affected by gravitational interactionwith the neighbouring blue compact dwarf galaxy NGC 1510. Our multiwavelength analysis provides new clues about local star-formation processes, the metal redistribution in the outer gaseous discs of spiral galaxies, the importance of galaxy interactions, the fate of the neutral gas and the chemical evolution in nearby galaxies.

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Atomic and molecular gas components in spiral galaxies of the Virgo cluster

Astronomy Letters ◽

10.1134/s1063773712020041 ◽

2012 ◽

Vol 38 (2) ◽

pp. 63-73 ◽

Cited By ~ 7

Author(s):

A. V. Kasparova

Keyword(s):

Spiral Galaxies ◽

Virgo Cluster ◽

Molecular Gas

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The effect of diffuse background on the spatially-resolved Schmidt relation in nearby spiral galaxies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732467 ◽

2020 ◽

Vol 634 ◽

pp. A24 ◽

Cited By ~ 4

Author(s):

Nimisha Kumari ◽

Mike J. Irwin ◽

Bethan L. James

Keyword(s):

Star Formation ◽

Galaxy Formation ◽

Spiral Galaxies ◽

Formation Rate ◽

Molecular Gas ◽

Nearby Galaxy ◽

Spatially Resolved ◽

Diffuse Background ◽

Nearby Galaxies ◽

Atomic Gas

Context. The global Schmidt law of star formation provides a power-law relation between the surface densities of star-formation rate (SFR) and gas, and successfully explains plausible scenarios of galaxy formation and evolution. However, star formation being a multi-scale process, requires spatially-resolved analysis for a better understanding of the physics of star formation. Aims. It has been shown that the removal of a diffuse background from SFR tracers, such as Hα, far-ultraviolet (FUV), infrared, leads to an increase in the slope of the sub-galactic Schmidt relation. We reinvestigate the local Schmidt relations in nine nearby spiral galaxies taking into account the effect of inclusion and removal of diffuse background in SFR tracers as well as in the atomic gas. Methods. We used multiwavelength data obtained as part of the Spitzer Infrared Nearby Galaxies Survey, Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel, The H I Nearby Galaxy Survey, and HERA CO-Line Extragalactic Survey. Making use of a novel split of the overall light distribution as a function of spatial scale, we subtracted the diffuse background in the SFR tracers as well as the atomic gas. Using aperture photometry, we study the Schmidt relations on background subtracted and unsubtracted data at physical scales varying between 0.5–2 kpc. Results. The fraction of diffuse background varies from galaxy to galaxy and accounts to ∼34% in Hα, ∼43% in FUV, ∼37% in 24 μm, and ∼75% in H I on average. We find that the inclusion of diffuse background in SFR tracers leads to a linear molecular gas Schmidt relation and a bimodal total gas Schmidt relation. However, the removal of diffuse background in SFR tracers leads to a super-linear molecular gas Schmidt relation. A further removal of the diffuse background from atomic gas results in a slope ∼1.4 ± 0.1, which agrees with dynamical models of star formation accounting for flaring effects in the outer regions of galaxies.

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The link between star formation and gas in nearby galaxies

Communications Physics ◽

10.1038/s42005-020-00493-0 ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Robert Feldmann

Keyword(s):

Star Formation ◽

Gas Content ◽

Molecular Gas ◽

Galaxy Mergers ◽

Physical Processes ◽

Star Forming ◽

Star Formation Activity ◽

Star Formation In Galaxies ◽

Nearby Galaxies ◽

Gas Accretion

AbstractObservations of the interstellar medium are key to deciphering the physical processes regulating star formation in galaxies. However, observational uncertainties and detection limits can bias the interpretation unless carefully modeled. Here I re-analyze star formation rates and gas masses of a representative sample of nearby galaxies with the help of multi-dimensional Bayesian modeling. Typical star forming galaxies are found to lie in a ‘star forming plane’ largely independent of their stellar mass. Their star formation activity is tightly correlated with the molecular and total gas content, while variations of the molecular-gas-to-star conversion efficiency are shown to be significantly smaller than previously reported. These data-driven findings suggest that physical processes that modify the overall galactic gas content, such as gas accretion and outflows, regulate the star formation activity in typical nearby galaxies, while a change in efficiency triggered by, e.g., galaxy mergers or gas instabilities, may boost the activity of starbursts.

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