CARMA Survey Toward Infrared-bright Nearby Galaxies STING: Molecular Gas Star Formation Law in NGC4254 - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




CARMA Survey Toward Infrared-bright Nearby Galaxies STING: Molecular Gas Star Formation Law in NGC4254 - Astrophysics > Cosmology and Nongalactic Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: This study explores the effects of different assumptions and systematics onthe determination of the local, spatially resolved star formation law. Usingfour star formation rate SFR tracers H\alpha with azimuthally averagedextinction correction, mid-infrared 24 micron, combined H\alpha andmid-infrared 24 micron, and combined far-ultraviolet and mid-infrared 24micron, several fitting procedures, and different sampling strategies we probethe relation between SFR and molecular gas at various spatial resolutions andsurface densities within the central 6.5 kpc in the disk of NGC4254. We findthat in the high surface brightness regions of NGC4254 the form of themolecular gas star formation law is robustly determined and approximatelylinear and independent of the assumed fraction of diffuse emission and the SFRtracer employed. When the low surface brightness regions are included, theslope of the star formation law depends primarily on the assumed fraction ofdiffuse emission. In such case, results range from linear when the fraction ofdiffuse emission in the SFR tracer is ~30% or less or when diffuse emission isremoved in both the star formation and the molecular gas tracer, tosuper-linear when the diffuse fraction is ~50% and above. We find that thetightness of the correlation between gas and star formation varies with thechoice of star formation tracer. The 24 micron SFR tracer by itself shows thetightest correlation with the molecular gas surface density, whereas theH\alpha corrected for extinction using an azimuthally-averaged correction showsthe highest dispersion. We find that for R<0.5R 25 the local star formationefficiency is constant and similar to that observed in other large spirals,with a molecular gas depletion time ~2 Gyr.



Autor: Nurur Rahman, Alberto D. Bolatto, Tony Wong, Adam K. Leroy, Fabian Walter, Erik Rosolowsky, Andrew A. West, Frank Bigiel, Juergen

Fuente: https://arxiv.org/



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