Connecting Dense Gas Tracers of Star Formation in our Galaxy to High-
                    <i>z</i>
                    Star Formation

Wu, Jingwen; Evans, Neal J.; Gao, Yu; Solomon, P. M.; Shirley, Yancy L.; Bout, P. A. Vanden

doi:10.1086/499623

Cited by 361 publications

(553 citation statements)

References 29 publications

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“…If SFR(radio) gives an accurate measure of SFR, then the results would mean that SFR(L T IR ) is a good tracer above 10 4.5 L ⊙ . This result would be consistent with the suggestion by Wu et al (2005b) that the L T IR traces star formation above that luminosity. Resolving YSOs in regions forming high mass stars is a next important step in further understanding of the use of these tracers.…”

Section: Combining Both Samplessupporting

confidence: 93%

TESTING 24 μm AND INFRARED LUMINOSITY AS STAR FORMATION TRACERS FOR GALACTIC STAR-FORMING REGIONS

Vutisalchavakul

Evans

2013

ApJ

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We have tested some relations for star formation rates used in extra-galactic studies for regions within the Galaxy. In nearby molecular clouds, where the IMF is not fully-sampled, the dust emission at 24 µm greatly underestimates star formation rates (by a factor of 100 on average) when compared to star formation rates determined from counting YSOs. The total infrared emission does no better. In contrast, the total far-infrared method agrees within a factor of 2 on average with star formation rates based on radio continuum emission for massive, dense clumps that are forming enough massive stars to have L T IR exceed 10 4.5 L ⊙ . The total infrared and 24 µm also agree well with each other for both nearby, low-mass star forming regions and the massive, dense clumps regions.

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Section: Combining Both Samplessupporting

confidence: 93%

TESTING 24 μm AND INFRARED LUMINOSITY AS STAR FORMATION TRACERS FOR GALACTIC STAR-FORMING REGIONS

Vutisalchavakul

Evans

2013

ApJ

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“…This interpretation was expanded upon by Wu et al (2005) and Wu et al (2010), who extended this study to dense clumps 20 within the Galaxy and found a similarly linear relation between L IR and HCN luminosity. Complementary work utilizing HCO + (J=3-2), which has a similar effective density as HCN (J=1-0) (Juneau et al, 2009), as well as high-visual extinction molecular gas as dense gas tracers have found roughly linear dense gas star formation laws for clumps within the Milky Way (Lada et al, 2010;Schenck et al, 2011).…”

Section: Physics Learned From the Milky Way And Local Galaxiesmentioning

confidence: 56%

Dusty star-forming galaxies at high redshift

2014

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Far-infrared and submillimeter wavelength surveys have now established the important role of dusty, star-forming galaxies (DSFGs) in the assembly of stellar mass and the evolution of massive galaxies in the Universe. The brightest of these galaxies have infrared luminosities in excess of 10 13 L with implied star-formation rates of thousands of solar masses per year. They represent the most intense starbursts in the Universe, yet many are completely optically obscured. Their easy detection at submm wavelengths is due to dust heated by ultraviolet radiation of newly forming stars. When summed up, all of the dusty, star-forming galaxies in the Universe produce an infrared radiation field that has an equal energy density as the direct starlight emission from all galaxies visible at ultraviolet and optical wavelengths. The bulk of this infrared extragalactic background light emanates from galaxies as diverse as gas-rich disks to mergers of intense starbursting galaxies. Major advances in far-infrared instrumentation in recent years, both spacebased and ground-based, has led to the detection of nearly a million DSFGs, yet our understanding of the underlying astrophysics that govern the start and end of the dusty starburst phase is still in nascent stage. This review is aimed at summarizing the current status of DSFG studies, focusing especially on the detailed characterization of the bestunderstood subset (submillimeter galaxies, who were summarized in the last review of this field over a decade ago, Blain et al. 2002), but also the selection and characterization of more recently discovered DSFG populations. We review DSFG population statistics, their physical properties including dust, gas and stellar contents, their environments, and current theoretical models related to the formation and evolution of these galaxies.

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“…Finally, our findings have also relevance for the extragalactic community, who make use of the HCN molecule to estimate the amount of dense molecular gas and correlate it to the star formation rate in galaxies (see Wu et al 2005, for a Galactic and extragalactic analysis on the matter). It is interesting that our mean value for the HCO + (1-0) to HCN(1-0) ratio of 0.74 for the IR-loud sub-sample is not greatly different than that (a median of 0.86) found by Krips et al (2008) for a sample of AGN and starburst galaxies (though with a variation from 0.48 to 1.5).…”

Section: Hco + (1-0) Versus Hcn(1-0)mentioning

confidence: 71%

“…HCN and HCO + are commonly used as tracers of the dense gas from which "bursts" of star formation emanate both in the Galactic and extragalactic contexts (Wu et al 2005;Gao & Solomon 2004). They have the advantage relative to CO that their dipole moments are high and hence that even their 3 mm transitions trace gas of density above ∼10 4 cm −3 .…”

Section: Hco + (1-0) Versus Hcn(1-0)mentioning

confidence: 99%

A comparative study of high-mass cluster forming clumps

López-Sepulcre

Cesaroni

Walmsley

2010

A&A

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Aims. We have searched for star formation activity (mainly infall and outflow signatures) in a sample of high-mass molecular clumps (M > 100 M ) in different evolutionary stages and with a wide range of surface densities, with the aim of looking for evolutionary trends and testing observationally recent theoretical models which predict the need for a minimum surface density to form high-mass stars. Methods. Our sample has been selected from single-dish 1.2 mm continuum surveys and is composed of 48 massive molecular clumps, of which 29 are IR-loud and 19 are IR-dark. Each of these has been mapped in the HCO + (1-0), HCN(1-0) and C 18 O(2-1) transitions with the IRAM-30 m telescope on Pico Veleta (Spain). We derive basic parameters (mass, momentum, kinetic energy) for the clumps and their associated outflows and examine the HCO + (1-0) line profiles for evidence of infall or expansion. Results. Molecular outflows have been detected in 75% of our targets from the presence of high-velocity wings in the HCO + (1-0) spectra. These are equally frequent and massive (between ∼1 and ∼100 M ) in IR-dark and IR-loud clumps, implying similar levels of star formation activity in both kinds of objects. A surface density threshold at Σ = 0.3 g cm −2 has been found above which the outflow detection rate increases significantly and the outflows are on average more massive. The infall detection rate in our sample is low, but significantly higher in the IR-dark sub-sample. Our clump mass estimates using the mm dust emission and C 18 O(2-1) are sensitive to the temperature, but assuming a value of 15 K for the IR-dark sub-sample, we find evidence that C 18 O is depleted by a factor ∼4.5. The HCO + (1-0) to HCN(1-0) integrated intensity ratios measured reveal a greater dispersion about the mean value in the IR-dark sub-sample than in the IR-loud by a factor of about 5. We find that a considerable number of IR-dark sources are self-absorbed in HCN(1-0) suggesting that radiative transport effects in the ground state transitions have an important influence on the integrated intensity ratio. Conclusions. Our results indicate that, in terms of outflow frequency and energetics, both IR-dark and IR-loud molecular clumps present equivalent signatures of star formation activity, and that the formation of high-mass stars requires sufficiently high clump surface densities. The higher infall detection rate measured for the IR-dark subsample suggests that these objects could be associated with the onset of star formation.

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Connecting Dense Gas Tracers of Star Formation in our Galaxy to High- z Star Formation

Cited by 361 publications

References 29 publications

TESTING 24 μm AND INFRARED LUMINOSITY AS STAR FORMATION TRACERS FOR GALACTIC STAR-FORMING REGIONS

TESTING 24 μm AND INFRARED LUMINOSITY AS STAR FORMATION TRACERS FOR GALACTIC STAR-FORMING REGIONS

Dusty star-forming galaxies at high redshift

A comparative study of high-mass cluster forming clumps

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