THE SUPER-LINEAR SLOPE OF THE SPATIALLY RESOLVED STAR FORMATION LAW IN NGC 3521 AND NGC 5194 (M51a)

Liu, Guilin; Koda, Jin; Calzetti, Daniela; Fukuhara, Masahiro; Momose, Rieko

doi:10.1088/0004-637x/735/1/63

Cited by 134 publications

(242 citation statements)

References 75 publications

(125 reference statements)

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“…For example, Liu et al (2011) argue that when one subtracts the diffuse component from SFR maps, then a super-linear resolved KS relation emerges in NGC 3251 and NGC 5194. On the other hand, Blanc et al (2009);Shetty et al (2013a,b) suggest that due to issues related to bisector fitting methods (which have been used in many of the resolved KS relation studies), the true KS slope should be sub-linear.…”

Section: Star Formation Laws and Efficienciesmentioning

confidence: 99%

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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Section: Star Formation Laws and Efficienciesmentioning

confidence: 99%

Dusty star-forming galaxies at high redshift

2014

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“…Other studies using 12 CO(2−1) also show a linear correlation (e.g., Leroy et al 2008;Schruba et al 2011), including one that combined single-dish 12 CO(2−1) data with interferometric 12 CO(1−0) data (Rahman et al 2011). These 12 CO(2−1) studies analyzed a substantial number of nearby galaxies, though it should be recognized that some studies based on 12 CO(1−0) data showed a superlinear (power-law) correlation, rather than a linear correlation (e.g., Wong & Blitz 2002;Kennicutt et al 2007;Liu et al 2011). This suggests that the choice of the CO transition for deriving Σ H 2 could affect N fit values (see Bigiel et al 2008).…”

Section: The K-s Relation Index: Resolution Vs 12 Co Transitionsmentioning

confidence: 99%

“…Spatially resolved K-S relation studies published in the past decade (e.g., Kennicutt et al 2007;Bigiel et al 2008Bigiel et al , 2010Bigiel et al , 2011Leroy et al 2008;Blanc et al 2009;Eales et al 2010;Verley et al 2010;Liu et al 2011;Rahman et al 2011Rahman et al , 2012Schruba et al 2011;Ford et al 2013;Viaene et al 2014) found a wide spread in the value of the power relation index (N ≈ 0.6−3) both within and among galaxies. For a comprehensive review of the most recent SF relation studies on sub-kpc scales, we refer to Kennicutt & Evans (2012).…”

Section: Introductionmentioning

confidence: 99%

The resolved star-formation relation in nearby active galactic nuclei

Casasola

Hunt

Combes

et al. 2015

A&A

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Aims. We present an analysis of the relation between the star formation rate (SFR) surface density (Σ SFR ) and mass surface density of molecular gas (Σ H 2 ), commonly referred to as the Kennicutt-Schmidt (K-S) relation, on its intrinsic spatial scale, i.e. the size of giant molecular clouds (∼10−150 pc), in the central, high-density regions of four nearby low-luminosity active galactic nuclei (AGN). These are AGN extracted from the NUclei of GAlaxies (NUGA) survey. This study investigates the correlations and slopes of the K-S relation, as a function of spatial resolution and of the different 12 CO emission lines used to trace Σ H 2 , and tests its validity in the high-density central regions of spiral galaxies. Methods. We used interferometric IRAM 12 CO(1−0) and 12 CO(2−1) and SMA 12 CO(3−2) emission line maps to derive Σ H 2 and HST-Hα images to estimate Σ SFR . Results. Each galaxy is characterized by a distinct molecular SF relation on spatial scales between 20 to 200 pc. The K-S relations can be sublinear, but also superlinear, with slopes ranging from ∼0.5 to ∼1.3; slopes are generally superlinear on spatial scales >100 pc and sublinear on smaller scales. Depletion times range from ∼1 and 2 Gyr, which is compatible with results for nearby normal galaxies. These findings are valid independently of which transition -12 CO(1−0), 12 CO(2−1), or 12 CO(3−2) -is used to derive Σ H 2 . Because of either star-formation feedback, the lifetime of clouds, turbulent cascade, or magnetic fields, the K-S relation might be expected to degrade on small spatial scales (<100 pc). However, we find no clear evidence of this, even on scales as small as ∼20 pc, and this might be because of the higher density of GMCs in galaxy centers that have to resist higher shear forces. The proportionality between Σ H 2 and Σ SFR found between 10 and 100 M pc −2 is valid even at high densities, ∼10 3 M pc −2 . However, by adopting a common CO-to-H 2 conversion factor (α CO ), the central regions of the NUGA galaxies have higher Σ SFR for a given gas column than those expected from the models, with a behavior that lies between the mergers or high-redshift starburst systems and the more quiescent star-forming galaxies, assuming that the first ones require a lower value of α CO .

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“…The same background was subtracted for all apertures. Recent studies of nearby galaxies have shown the importance of background subtraction to derive the star-formation laws (Blanc et al 2009;Rahman et al 2011;Liu et al 2011). However, this is most important for regions in galaxies forming stars at a low rate that can be resolved only in nearby galaxies.…”

Section: Himentioning

confidence: 99%

“…Whether and how this law varies is subject of an on-going debate in the literature (Kennicutt 1998b;Gao & Solomon 2004;Kennicutt et al 2007;Leroy et al 2008;Bigiel et al 2008;Blanc et al 2009;Rahman et al 2011;Liu et al 2011). Deviations between quiescent starforming galaxies and interacting systems can have important implications regarding our understanding of galaxy formation and evolution.…”

Section: Schmidt-kennicutt Lawmentioning

confidence: 99%

Studying the spatially resolved Schmidt-Kennicutt law in interacting galaxies: the case of Arp 158

Boquien¹,

Lisenfeld²,

Duc³

et al. 2011

A&A

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Context. Recent studies have shown that star formation in mergers does not seem to follow the same Schmidt-Kennicutt relation as in spiral disks, presenting a higher star formation rate (SFR) for a given gas column density. Aims. In this paper we study why and how different models of star formation arise. To do so we examine the process of star formation in the interacting system Arp 158 and its tidal debris. Methods. We perform an analysis of the properties of specific regions of interest in Arp 158 using observations tracing the atomic and the molecular gas, star formation, the stellar populations as well as optical spectroscopy to determine their exact nature and their metallicity. We also fit their spectral energy distribution with an evolutionary synthesis code. Finally, we compare star formation in these objects to star formation in the disks of spiral galaxies and mergers. Results. Abundant molecular gas is found throughout the system and the tidal tails appear to have many young stars compared to their old stellar content. One of the nuclei is dominated by a starburst whereas the other is an active nucleus. We estimate the SFR throughout the systems using various tracers and find that most regions follow closely the Schmidt-Kennicutt relation seen in spiral galaxies with the exception of the nuclear starburst and the tip of one of the tails. We examine whether this diversity is due to uncertainties in the manner the SFR is determined or whether the conditions in the nuclear starburst region are such that it does not follow the same Schmidt-Kennicutt law as other regions. Conclusions. Observations of the interacting system Arp 158 provide the first evidence in a resolved fashion that different star-forming regions in a merger may be following different Schmidt-Kennicutt laws. This suggests that the physics of the interstellar medium at a scale no larger than 1 kpc, the size of the largest gravitational instabilities and the injection scale of turbulence, determines the origin of these laws.

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THE SUPER-LINEAR SLOPE OF THE SPATIALLY RESOLVED STAR FORMATION LAW IN NGC 3521 AND NGC 5194 (M51a)

Cited by 134 publications

References 75 publications

Dusty star-forming galaxies at high redshift

Dusty star-forming galaxies at high redshift

The resolved star-formation relation in nearby active galactic nuclei

Studying the spatially resolved Schmidt-Kennicutt law in interacting galaxies: the case of Arp 158

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