Distances to Galactic High‐Velocity Clouds. I. Cohen Stream, Complex GCP, Cloud g1

Wakker, Bart P.; York, Donald G.; Wilhelm, Ronald; Barentine, John C.; Richter, Philipp; Beers, Timothy C.; Ivezić, Željko; Howk, J. C.

doi:10.1086/523845

Cited by 182 publications

(217 citation statements)

References 83 publications

Supporting

Mentioning

198

Contrasting

Order By: Relevance

“…Although not as spectacular as in IZw18, elongated extraplanar features are quite common in disk galaxies (e.g., NGC925, Pisano et al 1998, and the many other examples given in the review by Sancisi et al 2008). Extraplanar gas is also found in our own galaxy, where the existence of gas clouds falling in is long known (Oort 1966;Blitz et al 1999;van Woerden et al 2004;Wakker et al 2007Wakker et al , 2008. Some of these high velocity clouds (HVC) are part of the so-called galactic fountain, where SN ejecta return to the galaxy plane after cooling down (e.g., Tenorio-Tagle 1996; Spitoni et al 2008).…”

Section: Neutral Gas Observationsmentioning

confidence: 80%

Star formation sustained by gas accretion

Alméida

Elmegreen

Muñoz–Tuñón

et al. 2014

Astron Astrophys Rev

177

130

View full text Add to dashboard Cite

Numerical simulations predict that metal-poor gas accretion from the cosmic web fuels the formation of disk galaxies. This paper discusses how cosmic gas accretion controls star formation, and summarizes the physical properties expected for the cosmic gas accreted by galaxies. The paper also collects observational evidence for gas accretion sustaining star formation. It reviews evidence inferred from neutral and ionized hydrogen, as well as from stars. A number of properties characterizing large samples of star-forming galaxies can be explained by metal-poor gas accretion, in particular, the relationship among stellar mass, metallicity, and star-formation rate (the so-called fundamental metallicity relationship). They are put forward and analyzed. Theory predicts gas accretion to be particularly important at high redshift, so indications based on distant objects are reviewed, including the global star-formation history of the universe, and the gas around galaxies as inferred from absorption features in the spectra of background sources.

show abstract

Section: Neutral Gas Observationsmentioning

confidence: 80%

Star formation sustained by gas accretion

Alméida

Elmegreen

Muñoz–Tuñón

et al. 2014

Astron Astrophys Rev

177

130

View full text Add to dashboard Cite

show abstract

“…Tracers of ongoing accretion can also be found closer to home: many of the MW's high velocity clouds (HVCs) have low metallicity (Tripp et al 2003); together with the increasingly tight constraints on their distances (Wakker et al 2007(Wakker et al , 2008, the evidence is consistent with the idea that at least part of the HVC population is infalling primordial gas. HVC analogs have also been detected in the outskirts of M 31 (Thilker et al 2004).…”

mentioning

confidence: 76%

The Westerbork Hydrogen Accretion in LOcal GAlaxieS (HALOGAS) survey

Heald

Józsa

Serra

et al. 2011

A&A

194

239

View full text Add to dashboard Cite

We introduce a new, very deep neutral hydrogen (H i) survey being performed with the Westerbork Synthesis Radio Telescope (WSRT). The Westerbork Hydrogen Accretion in LOcal GAlaxieS (HALOGAS) Survey is producing an archive of some of the most sensitive H i observations available, on the angular scales which are most useful for studying faint, diffuse gas in and around nearby galaxies. The survey data are being used to perform careful modeling of the galaxies, characterizing their gas content, morphology, and kinematics, with the primary goal of revealing the global characteristics of cold gas accretion onto spiral galaxies in the local Universe. In this paper, we describe the survey sample selection, the data acquisition, reduction, and analysis, and present the data products obtained during our pilot program, which consists of UGC 2082, NGC 672, NGC 925, and NGC 4565. The observations reveal a first glimpse of the picture that the full HALOGAS project aims to illuminate: the properties of accreting H i in different types of spirals, and across a range of galactic environments. None of the pilot survey galaxies hosts an H i halo of the scale of NGC 891, but all show varying indications of halo gas features. We compare the properties of detected features in the pilot survey galaxies with their global characteristics, and discuss similarities and differences with NGC 891 and NGC 2403.

show abstract

“…Figure 5 shows an H I channel map from a recent 21cm survey made with the Green Bank Telescope (GBT). The cloud has a good distance estimate (Wakker et al, 2008), and thus a well defined mass and size; it is moving toward the Galactic plane, which it should intersect in ∼ 30 Myr if it is survives as a coherent entity (Lockman et al, 2008). Its mass in H I is ∼ 2 × 10 6 M and it has an ionized component with a similar mass detected in faint H α emission (Hill et al, 2009).…”

Section: The Smith Cloud -Accretion In Actionmentioning

confidence: 99%

Neutral Gas Accretion onto Nearby Galaxies

Lockman¹

2017

Gas Accretion Onto Galaxies

View full text Add to dashboard Cite

While there is no lack of evidence for the accretion of stellar systems onto nearby galaxies, direct evidence for the accretion of gas without stars is scarce. Here we consider an inventory of starless gas "clouds" in and around galaxies of the Local Group to discern their general properties and see how they might appear in distant systems. The conclusion is that accreting gas without stars is detected almost entirely within the circumgalactic medium of large galaxies and is rare otherwise. If our Local Group is any example, the best place to detect starless gas clouds is relatively close to galaxies.

show abstract

Distances to Galactic High‐Velocity Clouds. I. Cohen Stream, Complex GCP, Cloud g1

Cited by 182 publications

References 83 publications

Star formation sustained by gas accretion

Star formation sustained by gas accretion

The Westerbork Hydrogen Accretion in LOcal GAlaxieS (HALOGAS) survey

Neutral Gas Accretion onto Nearby Galaxies

Contact Info

Product

Resources

About