Star-Formation Measurements in Nearby Galaxies

2021 ◽  
pp. 145-158
Author(s):  
Daniela Calzetti
Keyword(s):  
Star Formation ◽  
Nearby Galaxies

Recovering the star formation history of galaxies through spectral fitting: Current challenges

2019 ◽  
Vol 15 (S359) ◽  
pp. 386-390
Author(s):  
Lucimara P. Martins
Keyword(s):  
Star Formation ◽  
Mass Function ◽  
Initial Mass Function ◽  
Star Formation History ◽  
Stellar Spectra ◽  
Spectral Fitting ◽  
Formation History ◽  
History Of ◽  
Nearby Galaxies ◽  
Extract Information

AbstractWith the exception of some nearby galaxies, we cannot resolve stars individually. To recover the galaxies star formation history (SFH), the challenge is to extract information from their integrated spectrum. A widely used tool is the full spectral fitting technique. This consists of combining simple stellar populations (SSPs) of different ages and metallicities to match the integrated spectrum. This technique works well for optical spectra, for metallicities near solar and chemical histories not much different from our Galaxy. For everything else there is room for improvement. With telescopes being able to explore further and further away, and beyond the optical, the improvement of this type of tool is crucial. SSPs use as ingredients isochrones, an initial mass function, and a library of stellar spectra. My focus are the stellar libraries, key ingredient for SSPs. Here I talk about the latest developments of stellar libraries, how they influence the SSPs and how to improve them.

VLA-ANGST: Star Formation History and ISM Feedback in Nearby Galaxies

2008 ◽  
pp. 321-322
Author(s):  
Jurgen Ott ◽  
Evan Skillman ◽  
Julianne Dalcanton ◽  
Fabian Walter ◽  
Andrew West ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation History ◽  
Formation History ◽  
Nearby Galaxies

scholarly journals SKA studies of nearby galaxies: star-formation, accretion processes and molecular gas across all environments

2015 ◽  
Author(s):  
Rob J. Beswick ◽  
Elias Brinks ◽  
Miguel Perez-Torres ◽  
Anita Richards ◽  
Susanne Aalto ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Gas ◽  
Nearby Galaxies

scholarly journals The Galactic Center compared with nuclei of nearby galaxies

2016 ◽  
Vol 11 (S322) ◽  
pp. 245-252 ◽  
Author(s):  
Francoise Combes
Keyword(s):  
Star Formation ◽  
Galactic Center ◽  
Galactic Nuclei ◽  
Molecular Outflows ◽  
Star Formation Activity ◽  
Nearby Galaxies

AbstractUnderstanding our Galactic Center is easier with insights from nearby galactic nuclei. Both the star formation activity in nuclear gas disks, driven by bars and nuclear bars, and the fueling of low-luminosity AGN, followed by feedback of jets, driving molecular outflows, were certainly present in our Galactic Center, which appears now quenched. Comparisons and diagnostics are reviewed, in particular of m = 2 and m = 1 modes, lopsidedness, different disk orientations, and fossil evidences of activity and feedback.

scholarly journals A MOLECULAR STAR FORMATION LAW IN THE ATOMIC-GAS-DOMINATED REGIME IN NEARBY GALAXIES

2011 ◽  
Vol 142 (2) ◽  
pp. 37 ◽  
Author(s):  
Andreas Schruba ◽  
Adam K. Leroy ◽  
Fabian Walter ◽  
Frank Bigiel ◽  
Elias Brinks ◽  
...  
Keyword(s):  
Star Formation ◽  
Nearby Galaxies ◽  
Atomic Gas

scholarly journals Supershells

1988 ◽  
Vol 101 ◽  
pp. 447-459
Author(s):  
Richard McCray
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Interstellar Medium ◽  
Milky Way ◽  
Disk Galaxy ◽  
Interstellar Gas ◽  
Irregular Galaxies ◽  
Nearby Galaxies ◽  
Gas Layer

AbstractRepeated supernovae from an OB association will, in a few ×107 yr, create a cavity of coronal gas in the interstellar medium, with radius > 100 pc, surrounded by a dense expanding shell of cool interstellar gas. Such a cavity will likely burst through the gas layer of a disk galaxy. Such holes and “supershells” have been observed in optical and H I radio emission maps of the Milky Way and other nearby galaxies. The gas swept up in the supershell is likely to become gravitationally unstable, providing a mechanism for propagating star formation that may be particularly effective in irregular galaxies.

scholarly journals THE STAR FORMATION LAW IN NEARBY GALAXIES ON SUB-KPC SCALES

2008 ◽  
Vol 136 (6) ◽  
pp. 2846-2871 ◽  
Author(s):  
F. Bigiel ◽  
A. Leroy ◽  
F. Walter ◽  
E. Brinks ◽  
W. J. G. de Blok ◽  
...  
Keyword(s):  
Star Formation ◽  
Nearby Galaxies

scholarly journals Scaling Relations between Gas and Star Formation in Nearby Galaxies

2010 ◽  
Vol 6 (S270) ◽  
pp. 327-334 ◽  
Author(s):  
Frank Bigiel ◽  
Adam Leroy ◽  
Fabian Walter
Keyword(s):  
Star Formation ◽  
Spatial Scales ◽  
Formation Rate ◽  
Star Forming ◽  
Multiple Regimes ◽  
Combining Data ◽  
Multi Wavelength ◽  
Nearby Galaxies ◽  
Physical Quantities ◽  
Individual Galaxy

AbstractHigh resolution, multi-wavelength maps of a sizeable set of nearby galaxies have made it possible to study how the surface densities of H i, H2 and star formation rate (ΣHI, ΣH2, ΣSFR) relate on scales of a few hundred parsecs. At these scales, individual galaxy disks are comfortably resolved, making it possible to assess gas-SFR relations with respect to environment within galaxies. ΣH2, traced by CO intensity, shows a strong correlation with ΣSFR and the ratio between these two quantities, the molecular gas depletion time, appears to be constant at about 2 Gyr in large spiral galaxies. Within the star-forming disks of galaxies, ΣSFR shows almost no correlation with ΣHI. In the outer parts of galaxies, however, ΣSFR does scale with ΣHI, though with large scatter. Combining data from these different environments yields a distribution with multiple regimes in Σgas – ΣSFR space. If the underlying assumptions to convert observables to physical quantities are matched, even combined datasets based on different SFR tracers, methodologies and spatial scales occupy a well define locus in Σgas – ΣSFR space.

scholarly journals High-J CO Intensity Measurements for Galaxies Observed by the Herschel FTS

2015 ◽  
Vol 11 (S315) ◽  
pp. 26-29
Author(s):  
Julia Kamenetzky ◽  
Naseem Rangwala ◽  
Jason Glenn ◽  
Philip Maloney ◽  
Alex Conley
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Raw Material ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
J 13 ◽  
Systematic Effects ◽  
Nearby Galaxies ◽  
Co Emission

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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