Star Formation in NGC 5194 (M51a). II. The Spatially Resolved Star Formation Law

By Robert C. Kennicutt Jr., D. Calzetti, F. Walter, G. Helou, D. Hollenbach, Lee Armus, G. Bendo, D. Dale, B. Draine, C. Engelbracht and 13 more. 2007

451 citations recorded by the source corpus.

We have studied the relationship between the star formation rate (SFR), surface density, and gas surface density in the spiral galaxy M51a (NGC 5194), using multiwavelength data obtained as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS). We introduce a new SFR index based on a linear combination of Hα emission-line and 24 μm continuum luminosities, which provides reliable extinction-corrected ionizing fluxes and SFR densities over a wide range of dust attenuations. The combination of these extinction-corrected SFR densities with aperture synthesis H I and CO maps has allowed us to probe the form of the spatially resolved star formation law on scales of 0.5-2 kpc. We find that the resolved SFR versus gas surface density relation is well represented by a Schmidt power law, which is similar in form and dispersion to the disk-averaged Schmidt law. We observe a comparably strong correlation of the SFR surface density with the molecular gas surface density, but no significant correlation with the surface density of atomic gas. The best-fitting slope of the Schmidt law varies from N = 1.37 to 1.56, with zero point and slope that change systematically with the spatial sampling scale. We tentatively attribute these variations to the effects of areal sampling and averaging of a nonlinear intrinsic star formation law. Our data can also be fitted by an alternative parameterization of the SFR surface density in terms of the ratio of gas surface density to local dynamical time, but with a considerable dispersion.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

• ENVIRONMENTAL DEPENDENCE OF THE KENNICUTT–SCHMIDT RELATION IN GALAXIES (2010, background): “…of the KS relation (besides the weak trends mentioned above) is in general agreement with observations, which indicate broadly consistent KS relations derived using different star formation indicators and a wide range of spatial averaging scales (e.g., Kennicutt et al. 2007; Bigiel et al. 2008).”
• Implementing molecular hydrogen in hydrodynamic simulations of galaxy formation (2012, background): “…the SFR toH2 at various spatial scales and across a wide sample of galaxies also found that the SFR correlates most strongly withH2 (Rownd & Young 1999; Murgia et al. 2002; Heyer et al. 2004; Gao & Solomon 2004; Kennicutt et al. 2007; Blanc et al. 2009; Warren et al. 2010; Bigiel et al. 2010).”
• Self-regulated star formation in galaxies via momentum input from massive stars (2011, result): “15 For example, the MW-like simulation is significantly steeper at low densities than the median relation, but quite similar to spatially resolved observations in M51 (Kennicutt et al. 2007).”
• PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS IN z ∼ 1–3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES (2012, background): “This Kennicutt-Schmidt (‘KS’) – relation, Σstar_form~( Σmol_gas) N , N~1..1.4 (Kennicutt et al. 2007, Bigiel et al. 2008, Leroy et al. 2008, Kennicutt & Evans 2012) has a scatter of ±0.3..0.4 dex.”
• THE SINS SURVEY OF z ∼ 2 GALAXY KINEMATICS: PROPERTIES OF THE GIANT STAR-FORMING CLUMPS (2010, methodology): “We estimated molecular surface densities (and masses, including a 36% helium contribution) from Equation (8) of Kennicutt et al. (2007), modified for the Chabrier IMF used here, log ( Σmol−gas M pc−2 ) = 0.73 log ( Σstar−form M yr−1 kpc−2 ) + 2.91.”
• A general model for the CO–H2 conversion factor in galaxies with applications to the star formation law (2011, background): “The low-z disc observations (black filled circles and black triangles) come from Kennicutt et al. (2007), Wong & Blitz (2002), Crosthwaite & Turner (2007), Schuster et al. (2007) and comprise both resolved and unresolved points.”
• An Overview of the Dwarf Galaxy Survey (2013, background): “Evidence is growing for molecular gas surface density, in particular, as the regulator for star formation in galaxies of the local Universe as well as at high-redshift, and not necessarily the total gas density (e.g., Kennicutt et al. 2007; Bigiel et al. 2008; Genzel et al. 2012).”
• METALLICITY-DEPENDENT QUENCHING OF STAR FORMATION AT HIGH REDSHIFT IN SMALL GALAXIES (2011, background): “In the past decade, observations of star formation in nearby galaxies have unambiguously revealed that star formation is associated with the molecular phase of a galaxy’s interstellar medium (ISM) (Wong & Blitz 2002; Kennicutt et al. 2007; Leroy et al. 2008; Bigiel et al. 2008).”
• What controls star formation in the central 500 pc of the Galaxy (2013, background): “There are indications that the threshold density for gravitational i stability not only applies globally, but also locally for the spiral arms and the inter-arm regions of M51 (Kennicutt et al. 2007).”
• A WIDE-FIELD HIGH-RESOLUTION H i MOSAIC OF MESSIER 31. I. OPAQUE ATOMIC GAS AND STAR FORMATION RATE DENSITY (2009, methodology): “This differs from the procedure adopted by Kennicutt et al. (2007), (hereafter K07) who keep the comparison in terms of hydrogen nuclei (rather than including a Helium mass correction).”
• THE STAR FORMATION RATE AND GAS SURFACE DENSITY RELATION IN THE MILKY WAY: IMPLICATIONS FOR EXTRAGALACTIC STUDIES (2010, background): “Current “spatially resolved” extragalactic measurements are still limited to scales of ∼0.2-2 kpc (Kennicutt et al. 2007; Bigiel et al. 2008; Blanc et al. 2009); therefore, we cannot directly measure extragalactic SFRs on scales of galactic star forming regions.”
• How supernova feedback turns dark matter cusps into cores (2011, background): “…LT’s threshold of 0.1cm−3 represents an approximate historical norm for galaxy formation simulations (e.g. Navarro & White 1993; Katz et al. 1996) broadly compatible with the observed cut-off in star formation at low column densities averaged over ∼ kpc scales (e.g. Kennicutt et al. 2007).”
• On the impact of empirical and theoretical star formation laws on galaxy formation (2010, background): “Improvements in the quality and quantity of observations of the spatially resolved SFRs and atomic and molecular gas contents in local galaxies (e.g. Kennicutt et al. 2007; Bigiel et al. 2008) have allowed the development of both empirical (e.g. BR06; Leroy et al. 2008) and theoretical SF models…”
• THE SCALE DEPENDENCE OF THE MOLECULAR GAS DEPLETION TIME IN M33 (2010, methodology): “Support for AKL was provided by NASA through Hubble Fellowship grant HST-HF-51258.”
• Physical properties and environments of nearby galaxies (2009, methodology): “…observations with Spitzer and GALEX have led to a new class of hybrid SFR indicators that use a weighted combination of UV/optical and infrared luminosity to minimize the systematic effects of dust obscuration (Gordon et al. 2000; Kennicutt et al. 2007; Calzetti et al. 2007; Rieke et al. 2008.”
• On the relation between the Schmidt and Kennicutt-Schmidt star formation laws and its implications for numerical simulations (2007, background): “…averaged in radial bins (e.g. Zhang, Fall, & Whitmore 2001; Wong & Blitz 2002; Komugi et al. 2005; Boissier et al. 2006; Schuster et al. 2007) and even when they are measured in local cylindrical bins, although in that case the coefficient A may be somewhat smaller (Kennicutt et al. 2007).”
• Theoretical Challenges in Galaxy Formation (2016, background): “…couple the star formation rate to molecular gas properties inspired by observed connections (Bigiel et al. 2008, Kennicutt & Evans 2012, Kennicutt et al. 2007, Leroy et al. 2008, Wong & Blitz 2002) and use a constant time-scale in combination with the variable local H2 fraction (e.g.…”
• Star Formation in the Milky Way and Nearby Galaxies (2012, background): “Other authors however have reported steeper dependences (N = 1.2–1.7), closer to those seen in integrated measurements (e.g., Kennicutt et al. 2007; Verley et al. 2010; Rahman et al. 2011; Liu et al. 2011; Momose 2012).”