EMBEDDED STAR FORMATION IN S<sup>4</sup>G GALAXY DUST LANES

Elmegreen, D. M.; Elmegreen, Bruce G.; Erroz-Ferrer, Santiago; Knapen, Johan H.; Teich, Yaron; Popinchalk, Mark; Athanassoula, E.; Bosma, A.; Comerón, Sébastien; Efremov, Yu. N.; Gadotti, Dimitri A.; Paz, A. Gil de; Hinz, J. L.; Ho, Luis C.; Holwerda, Benne W.; Kim, Tae Hyun; Laine, Jarkko; Laurikainen, Eija; Menéndez‐Delmestre, Karín; Mizusawa, Trisha; Muñoz-Mateos, J. C.; Regan, Michael W.; Salo, H.; Seibert, Mark; Sheth, Kartik

doi:10.1088/0004-637x/780/1/32

Cited by 21 publications

(19 citation statements)

References 72 publications

(107 reference statements)

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“…Our derived average GMC masses in spurs S2 and S6 are at the lower (∼1×10 6  M ) and higher (∼4×10 6  M ) end of gas masses observed. However, in any case, they are well below the 10 7  M inferred by Elmegreen et al (2014) for these regions. In order to infer an estimate of the star formation efficiency (SFE), we compare the average mass in GMCs to that in young stellar clusters.…”

Section: Formation and Evolution Of Gas Spursmentioning

confidence: 55%

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The PdBI Arcsecond Whirlpool Survey (PAWS): The Role of Spiral Arms in Cloud and Star Formation

Schinnerer

Meidt

Colombo

et al. 2017

ApJ

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The process that leads to the formation of the bright star-forming sites observed along prominent spiral arms remains elusive. We present results of a multi-wavelength study of a spiral arm segment in the nearby grand-design spiral galaxy M51 that belongs to a spiral density wave and exhibits nine gas spurs. The combined observations of the (ionized, atomic, molecular, dusty) interstellar medium with star formation tracers (H II regions, young <10 Myr stellar clusters) suggest (1) no variation in giant molecular cloud (GMC) properties between arm and gas spurs, (2) gas spurs and extinction feathers arising from the same structure with a close spatial relation between gas spurs and ongoing/recent star formation (despite higher gas surface densities in the spiral arm), (3) no trend in star formation age either along the arm or along a spur, (4) evidence for strong star formation feedback in gas spurs, (5) tentative evidence for star formation triggered by stellar feedback for one spur, and (6) GMC associations being not special entities but the result of blending of gas arm/spur cross sections in lower resolution observations. We conclude that there is no evidence for a coherent star formation onset mechanism that can be solely associated with the presence of the spiral density wave. This suggests that other (more localized) mechanisms are important to delay star formation such that it occurs in spurs. The evidence of star formation proceeding over several million years within individual spurs implies that the mechanism that leads to star formation acts or is sustained over a longer timescale.

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Section: Formation and Evolution Of Gas Spursmentioning

confidence: 55%

“…For example, Elmegreen et al (2014) analyzed ∼2″ resolution 3.6 μm, Hα and SDSS images to identify the youngest star-forming sites along spiral arms in five nearby spiral galaxies including M51. Their embedded sources 1 and 2 correspond to our spurs S2 and S6.…”

Section: Formation and Evolution Of Gas Spursmentioning

confidence: 99%

The PdBI Arcsecond Whirlpool Survey (PAWS): The Role of Spiral Arms in Cloud and Star Formation

Schinnerer

Meidt

Colombo

et al. 2017

ApJ

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“…The connections between these dense parts and their surrounding gas can reveal the processes involved. If the cloud is part of a shell (Palmeirim, et al 2017), converging flow (Whitworth et al 2018) or spiral arm shock front (Elmegreen et al 2014), then the clouds are likely to have been formed or influenced by the associated pressures, after which gravity could have made the central parts dense enough for star formation. If disk gravitational instabilities generate spiral arms and filaments that fragment into molecular clouds, then even the birth of these complexes might be driven by gravity out to the edges of their HI envelopes.…”

Section: Introductionmentioning

confidence: 99%

Probability distribution functions of gas surface density in M 33

Corbelli

Elmegreen²,

Braine

et al. 2018

A&A

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Aims. We examine the interstellar medium (ISM) of M33 to unveil fingerprints of self-gravitating gas clouds across the star-forming disk.Methods. The probability distribution functions (PDFs) for atomic, molecular, and total gas surface densities are determined at a resolution of about 50 pc from available HI and CO emission line data over regions that share coherent morphological properties and considering cloud samples at different evolutionary stages along the star formation cycle. Results. Most of the total gas PDFs from the central region to the edge of the star-forming disk are well-fitted by log-normal functions whose width decreases radially outwards. Because the HI velocity dispersion is approximately constant across the disk, the decrease of the PDF width is consistent with a lower Mach number for the turbulent ISM at large galactocentric radii where a higher fraction of HI is in the warm phase. The atomic gas is found mostly at face-on column densities below N lim H = 2.5 10 21 cm −2 , with small radial variations of N lim H . The molecular gas PDFs do not show strong deviations from log-normal functions in the central region where molecular fractions are high. Here the high pressure and rate of star formation shapes the PDF as a log-normal function dispersing self-gravitating complexes with intense feedback at all column densities that are spatially resolved. Power law PDFs for the molecules are found near and above N lim H , in the well defined southern spiral arm and in a continuous dense filament extending at larger galactocentric radii. In the filament nearly half of the molecular gas departs from a log-normal PDF and power laws are also observed in pre-star forming molecular complexes. The slope of the power law is between −1 and −2. This slope, combined with maps showing where the different parts of the power law PDFs come from, suggest a power-law stratification of density within molecular cloud complexes, which is consistent with the dominance of self-gravity.

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“…These properties, tightly dependent upon each other, determine the gravitational self-binding and stellar and gas content of newly-born star clusters and stellar associations, as well as their conspicuous structures. It has long been known that large stellar structures, named stellar complexes, are the prominent signposts of star formation in galactic disks (e.g., van den Bergh 1964;Efremov 1989;Elmegreen et al 2014). These stellar structures trace star formation over several orders of magnitude in length-scales, and their characteristics relate to both the global galactic properties (dynamics, gas reservoir) and local environmental conditions (turbulent cascade, feedback) that regulate star formation (see, e.g., Mac Low & Klessen 2004).…”

Section: Introductionmentioning

confidence: 99%

Hierarchical star formation across the grand-design spiral NGC 1566

Gouliermis

Elmegreen²,

Elmegreen

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We investigate how star formation is spatially organized in the grand-design spiral NGC 1566 from deep HST photometry with the Legacy ExtraGalactic UV Survey (LEGUS). Our contour-based clustering analysis reveals 890 distinct stellar conglomerations at various levels of significance. These star-forming complexes are organized in a hierarchical fashion with the larger congregations consisting of smaller structures, which themselves fragment into even smaller and more compact stellar groupings. Their size distribution, covering a wide range in length-scales, shows a power-law as expected from scale-free processes. We explain this shape with a simple "fragmentation and enrichment" model. The hierarchical morphology of the complexes is confirmed by their mass-size relation which can be represented by a powerlaw with a fractional exponent, analogous to that determined for fractal molecular clouds. The surface stellar density distribution of the complexes shows a log-normal shape similar to that for supersonic non-gravitating turbulent gas. Between 50 and 65 per cent of the recentlyformed stars, as well as about 90 per cent of the young star clusters, are found inside the stellar complexes, located along the spiral arms. We find an age-difference between young stars inside the complexes and those in their direct vicinity in the arms of at least 10 Myr. This timescale may relate to the minimum time for stellar evaporation, although we cannot exclude the in situ formation of stars. As expected, star formation preferentially occurs in spiral arms. Our findings reveal turbulent-driven hierarchical star formation along the arms of a grand-design galaxy.

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EMBEDDED STAR FORMATION IN S⁴G GALAXY DUST LANES

Cited by 21 publications

References 72 publications

The PdBI Arcsecond Whirlpool Survey (PAWS): The Role of Spiral Arms in Cloud and Star Formation

The PdBI Arcsecond Whirlpool Survey (PAWS): The Role of Spiral Arms in Cloud and Star Formation

Probability distribution functions of gas surface density in M 33

Hierarchical star formation across the grand-design spiral NGC 1566

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EMBEDDED STAR FORMATION IN S4G GALAXY DUST LANES

Cited by 21 publications

References 72 publications

The PdBI Arcsecond Whirlpool Survey (PAWS): The Role of Spiral Arms in Cloud and Star Formation

The PdBI Arcsecond Whirlpool Survey (PAWS): The Role of Spiral Arms in Cloud and Star Formation

Probability distribution functions of gas surface density in M 33

Hierarchical star formation across the grand-design spiral NGC 1566

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Product

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About

EMBEDDED STAR FORMATION IN S⁴G GALAXY DUST LANES