scholarly journals DIISC-II: Unveiling the Connections between Star Formation and Interstellar Medium in the Extended Ultraviolet Disk of NGC 3344

2021 ◽  
Vol 923 (2) ◽  
pp. 199
Author(s):  
Mansi Padave ◽  
Sanchayeeta Borthakur ◽  
Hansung B. Gim ◽  
Rolf A. Jansen ◽  
David Thilker ◽  
...  
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Formation Rate ◽  
Gas Flows ◽  
Metal Line ◽  
Long Time ◽  
Circumgalactic Medium ◽  
Far Ultraviolet ◽  
Disk Growth ◽  
Stellar Complexes

Abstract We present our investigation of the extended ultraviolet (XUV) disk galaxy, NGC 3344, conducted as part of Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium survey. We use surface and aperture photometry of individual young stellar complexes to study star formation and its effect on the physical properties of the interstellar medium. We measure the specific star formation rate (sSFR) and find it to increase from 10−10 yr−1 in the inner disk to >10−8 yr−1 in the extended disk. This provides evidence for inside-out disk growth. If these sSFRs are maintained, the XUV disk stellar mass can double in ∼0.5 Gyr, suggesting a burst of star formation. The XUV disk will continue forming stars for a long time due to the high gas depletion times (τ dep). The stellar complexes in the XUV disk have high-ΣH I and low-ΣSFR with τ dep ∼ 10 Gyr, marking the onset of a deviation from the traditional Kennicutt–Schmidt law. We find that both far-ultraviolet (FUV) and a combination of FUV and 24 μm effectively trace star formation in the XUV disk. Hα is weaker in general and prone to stochasticities in the formation of massive stars. Investigation of the circumgalactic medium at 29.5 kpc resulted in the detection of two absorbing systems with metal-line species: the stronger absorption component is consistent with gas flows around the disk, most likely tracing inflow, while the weaker component is likely tracing corotating circumgalactic gas.

scholarly journals The GALEX -VVDS Measurement of the Evolution of the Far-Ultraviolet Luminosity Density and the Cosmic Star Formation Rate

2005 ◽  
Vol 619 (1) ◽  
pp. L47-L50 ◽  
Author(s):  
D. Schiminovich ◽  
O. Ilbert ◽  
S. Arnouts ◽  
B. Milliard ◽  
L. Tresse ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Far Ultraviolet

scholarly journals Turbulent structure and star formation in a stratified, supernova-driven, interstellar medium

2006 ◽  
Vol 2 (S237) ◽  
pp. 358-362
Author(s):  
M. K. Ryan Joung ◽  
Mordecai-Mark Mac Low
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Adaptive Mesh Refinement ◽  
Formation Rate ◽  
Three Dimensional ◽  
Adaptive Mesh ◽  
Mass Function ◽  
Initial Mass Function ◽  
Interstellar Turbulence ◽  
Self Gravity

AbstractWe report on a study of interstellar turbulence driven by both correlated and isolated supernova explosions. We use three-dimensional hydrodynamic models of a vertically stratified interstellar medium run with the adaptive mesh refinement code Flash at a maximum resolution of 2 pc, with a grid size of 0.5 × 0.5 × 10 kpc. Cold dense clouds form even in the absence of self-gravity due to the collective action of thermal instability and supersonic turbulence. Studying these clouds, we show that it can be misleading to predict physical properties such as the star formation rate or the stellar initial mass function using numerical simulations that do not include self-gravity of the gas. Even if all the gas in turbulently Jeans unstable regions in our simulation is assumed to collapse and form stars in local freefall times, the resulting total collapse rate is significantly lower than the value consistent with the input supernova rate. The amount of mass available for collapse depends on scale, suggesting a simple translation from the density PDF to the stellar IMF may be questionable. Even though the supernova-driven turbulence does produce compressed clouds, it also opposes global collapse. The net effect of supernova-driven turbulence is to inhibit star formation globally by decreasing the amount of mass unstable to gravitational collapse.

scholarly journals The diversity and variability of star formation histories in models of galaxy evolution

2020 ◽  
Vol 498 (1) ◽  
pp. 430-463 ◽  
Author(s):  
Kartheik G Iyer ◽  
Sandro Tacchella ◽  
Shy Genel ◽  
Christopher C Hayward ◽  
Lars Hernquist ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Time Scales ◽  
Formation Rate ◽  
Power Laws ◽  
Stellar Mass ◽  
Physical Processes ◽  
Long Time ◽  
Hydrodynamical Simulations ◽  
Star Formation Histories

ABSTRACT Understanding the variability of galaxy star formation histories (SFHs) across a range of time-scales provides insight into the underlying physical processes that regulate star formation within galaxies. We compile the SFHs of galaxies at z = 0 from an extensive set of models, ranging from cosmological hydrodynamical simulations (Illustris, IllustrisTNG, Mufasa, Simba, EAGLE), zoom simulations (FIRE-2, g14, and Marvel/Justice League), semi-analytic models (Santa Cruz SAM) and empirical models (UniverseMachine), and quantify the variability of these SFHs on different time-scales using the power spectral density (PSD) formalism. We find that the PSDs are well described by broken power laws, and variability on long time-scales (≳1 Gyr) accounts for most of the power in galaxy SFHs. Most hydrodynamical models show increased variability on shorter time-scales (≲300 Myr) with decreasing stellar mass. Quenching can induce ∼0.4−1 dex of additional power on time-scales >1 Gyr. The dark matter accretion histories of galaxies have remarkably self-similar PSDs and are coherent with the in situ star formation on time-scales >3 Gyr. There is considerable diversity among the different models in their (i) power due to star formation rate variability at a given time-scale, (ii) amount of correlation with adjacent time-scales (PSD slope), (iii) evolution of median PSDs with stellar mass, and (iv) presence and locations of breaks in the PSDs. The PSD framework is a useful space to study the SFHs of galaxies since model predictions vary widely. Observational constraints in this space will help constrain the relative strengths of the physical processes responsible for this variability.

scholarly journals MAGPHYS: a publicly available tool to interpret observed galaxy SEDs

2011 ◽  
Vol 7 (S284) ◽  
pp. 292-296 ◽  
Author(s):  
Elisabete da Cunha ◽  
Stéphane Charlot ◽  
Loretta Dunne ◽  
Dan Smith ◽  
Kate Rowlands
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Bayesian Method ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Dust Content ◽  
Stellar Content ◽  
Star Formation Activity ◽  
Infrared Wavelengths ◽  
User Friendly

AbstractWe present a simple, physically-motivated model to interpret consistently the emission from galaxies at ultraviolet, optical and infrared wavelengths. We combine this model with a Bayesian method to obtain robust statistical constraints on key parameters describing the stellar content, star formation activity and dust content of galaxies. Our model is now publicly available via a user-friendly code package, MAGPHYS at www.iap.fr/magphys. We present an application of this model to interpret a sample of ~1400 local (z<0.5) galaxies from the H-ATLAS survey. We find that, for these galaxies, the diffuse interstellar medium, powered mainly by stars older than 10 Myr, accounts for about half the total infrared luminosity. We discuss the implications of this result to the use of star formation rate indicators based on total infrared luminosity.

scholarly journals Radial Motions and Radial Gas Flows in Local Spiral Galaxies

2021 ◽  
Vol 923 (2) ◽  
pp. 220
Author(s):  
Enrico M. Di Teodoro ◽  
J. E. G. Peek
Keyword(s):  
Star Formation ◽  
Mass Flow ◽  
Spiral Galaxies ◽  
Formation Rate ◽  
High Sensitivity ◽  
Gas Flows ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Hydrogen Emission Line ◽  
Sensitivity Data

Abstract We determine radial velocities and mass flow rates in a sample of 54 local spiral galaxies by modeling high-resolution and high-sensitivity data of the atomic hydrogen emission line. We found that, although radial inflow motions seem to be slightly preferred over outflow motions, their magnitude is generally small. Most galaxies show radial flows of only a few km s−1 throughout their H i disks, either inward or outward, without any clear increase in magnitude in the outermost regions, as we would expect for continuous radial accretion. Gas mass flow rates for most galaxies are less than 1 M ⊙ yr−1. Over the entire sample, we estimated an average inflow rate of 0.3 M ⊙ yr−1 outside the optical disk and of 0.1 M ⊙ yr−1 in the outskirts of the H i disks. These inflow rates are about 5–10 times smaller than the average star formation rate of 1.4 M ⊙ yr−1. Our study suggests that there is no clear evidence for systematic radial accretion inflows that alone could feed and sustain the star formation process in the inner regions of local spiral galaxies at its current rate.

scholarly journals Enhanced galactic star formation as caused by the Milky Way - Large Magellanic Cloud interaction: an experience from density wave studies

1991 ◽  
Vol 148 ◽  
pp. 440-440
Author(s):  
L. S. Marochnik ◽  
A. A. Suchkov
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Formation Rate ◽  
Density Wave ◽  
Wave Theory ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Gas Flows ◽  
Andromeda Nebula ◽  
Density Wave Theory

Star formation in interacting galaxies is usually strongly enhanced. The star formation rate in the Milky Way is substantially greater than, for example, in the Andromeda Nebula. A plausible cause for this difference may be the interaction of the Milky Way with the Large Magellanic Cloud. We suggest that one of the possibilities for this may be the enhanced formation of cold gas clouds as the gas flows through the gravitational potential well of a tidal wave caused by the interaction; another contribution may come from compression of pre-existing clouds when they pass this way. This scenario is obviously quite similar to that envisioned in “frames” of the density-wave theory.

scholarly journals Disentangling the multiphase circumgalactic medium shared between a dwarf and a massive star-forming galaxy at z∼0.4

2020 ◽  
Vol 500 (3) ◽  
pp. 3987-3998
Author(s):  
Hasti Nateghi ◽  
Glenn G Kacprzak ◽  
Nikole M Nielsen ◽  
Sowgat Muzahid ◽  
Christopher W Churchill ◽  
...  
Keyword(s):  
Star Formation ◽  
Dwarf Galaxy ◽  
Formation Rate ◽  
Complex Nature ◽  
Star Forming ◽  
Galaxy Groups ◽  
Physical Mechanisms ◽  
High Ionization ◽  
Wide Range ◽  
Circumgalactic Medium

ABSTRACT The multiphase circumgalactic medium (CGM) arises within the complex environment around a galaxy, or collection of galaxies, and possibly originates from a wide range of physical mechanisms. In this paper, we attempt to disentangle the origins of these multiphase structures and present a detailed analysis of the quasar field Q0122−003 field using Keck/KCWI galaxy observations and HST/COS spectra probing the CGM. Our re-analysis of this field shows that there are two galaxies associated with the absorption. We have discovered a dwarf galaxy, G_27kpc (M⋆ = 108.7 M⊙), at z = 0.39863 that is 27 kpc from the quasar sightline. G_27kpc is only +21 km s−1 from a more massive (M⋆ = 1010.5 M⊙) star-forming galaxy, G_163kpc, at an impact parameter of 163 kpc. While G_163kpc is actively forming stars (SFR = 6.9 M⊙ yr−1), G_27kpc has a low star-formation rate (SFR = 0.08 ± 0.03 M⊙ yr−1) and star formation surface density (ΣSFR = 0.006 M⊙ kpc−2 yr−1), implying no active outflows. By comparing galaxy SFRs, kinematics, masses, and distances from the quasar sightline to the absorption kinematics, column densities, and metallicities, we have inferred the following: (1) Part of the low-ionization phase has a metallicity and kinematics consistent with being accreted on to G_27kpc. (2) The remainder of the low ionization phase has metallicities and kinematics consistent with being intragroup gas being transferred from G_27kpc to G_163kpc. (3) The high ionization phase is consistent with being produced solely by outflows originating from the massive halo of G_163kpc. Our results demonstrate the complex nature of the multiphase CGM, especially around galaxy groups, and that detailed case-by-case studies are critical for disentangling its origins.

scholarly journals Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR

2019 ◽  
Vol 622 ◽  
pp. A8 ◽  
Author(s):  
V. Heesen ◽  
E. Buie II ◽  
C. J. Huff ◽  
L. A. Perez ◽  
J. G. Woolsey ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Low Frequency ◽  
Cosmic Ray ◽  
Radio Continuum ◽  
Gaussian Kernel ◽  
Spatially Resolved ◽  
Sky Survey ◽  
Inverse Compton ◽  
Far Ultraviolet

Context. Radio continuum (RC) emission in galaxies allows us to measure star formation rates (SFRs) unaffected by extinction due to dust, of which the low-frequency part is uncontaminated from thermal (free–free) emission. Aims. We calibrate the conversion from the spatially resolved 140 MHz RC emission to the SFR surface density (ΣSFR) at 1 kpc scale. Radio spectral indices give us, by means of spectral ageing, a handle on the transport of cosmic rays using the electrons as a proxy for GeV nuclei. Methods. We used recent observations of three galaxies (NGC 3184, 4736, and 5055) from the LOFAR Two-metre Sky Survey (LoTSS), and archival LOw-Frequency ARray (LOFAR) data of NGC 5194. Maps were created with the facet calibration technique and converted to radio ΣSFR maps using the Condon relation. We compared these maps with hybrid ΣSFR maps from a combination of GALEX far-ultraviolet and Spitzer 24 μm data using plots tracing the relation at the highest angular resolution allowed by our data at 1.2 × 1.2 kpc2 resolution. Results. The RC emission is smoothed with respect to the hybrid ΣSFR owing to the transport of cosmic-ray electrons (CREs) away from star formation sites. This results in a sublinear relation (ΣSFR)RC ∝ [(ΣSFR)hyb]a, where a = 0.59 ± 0.13 (140 MHz) and a = 0.75 ± 0.10 (1365 MHz). Both relations have a scatter of σ = 0.3 dex. If we restrict ourselves to areas of young CREs (α >  −0.65; Iν ∝ να), the relation becomes almost linear at both frequencies with a ≈ 0.9 and a reduced scatter of σ = 0.2 dex. We then simulate the effect of CRE transport by convolving the hybrid ΣSFR maps with a Gaussian kernel until the RC–SFR relation is linearised; CRE transport lengths are l = 1–5 kpc. Solving the CRE diffusion equation, assuming dominance of the synchrotron and inverse-Compton losses, we find diffusion coefficients of D = (0.13–1.5)  × 1028 cm2 s−1 at 1 GeV. Conclusions. A RC–SFR relation at 1.4 GHz can be exploited to measure SFRs at redshift z ≈ 10 using 140 MHz observations.

scholarly journals Evidence for galaxy quenching in the green valley caused by a lack of a circumgalactic medium

2020 ◽  
Vol 500 (2) ◽  
pp. 2289-2301
Author(s):  
Glenn G Kacprzak ◽  
Nikole M Nielsen ◽  
Hasti Nateghi ◽  
Christopher W Churchill ◽  
Stephanie K Pointon ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Major Axis ◽  
Disc Galaxy ◽  
High Ionization ◽  
The Galaxy ◽  
Low Probability ◽  
Circumgalactic Medium ◽  
Quenching Time ◽  
The Relationship

ABSTRACT The relationship between a galaxy’s properties and its circumgalactic medium (CGM) provides a unique view of how galaxies evolve. We present an interesting edge-on (i = 86°) disc galaxy (G1547) where the CGM is probed by a background quasar at a distance of 84 kpc and within 10° of the galaxy major axis. G1547 does not have any detectable CGM absorption down to stringent limits, covering H i (EWr &lt;0.02 Å, log(N(H i)/cm−2) &lt; 12.6) and a range of low and high ionization absorption lines (O i, C ii, N ii, Si ii, C iii, N iii, Si iii, C iv, Si iv, N v, and O vi). This system is rare, given the covering fraction of $1.00_{-0.04}^{+0.00}$ for sub-L* galaxies within 50–100 kpc of quasar sightlines. G1547 has a low star formation rate (SFR, 1.1 M⊙ yr−1), specific SFR (sSFR, 1.5 × 10−10 yr−1), and ΣSFR (0.06 M⊙ yr−1 kpc−2) and does not exhibit active galactic nucleus or star-formation-driven outflows. Compared to the general population of galaxies, G1547 is in the green valley and has an above average metallicity with a negative gradient. When compared to other H i absorption-selected galaxies, we find that quiescent galaxies with log(sSFR/yr−1) &lt; −11 have a low probability (4/12) of possessing detectable H i in their CGM, while all galaxies (40/40) with log(sSFR/yr−1) &gt; −11 have H i absorption. We conclude that sSFR is a good indicator of the presence of H i CGM. Interestingly however, G1547 is the only galaxy with log(sSFR/yr−1) &gt; −11 that has no detectable CGM. Given the properties of G1547, and its absent CGM, it is plausible that G1547 is undergoing quenching due to a lack of accreting fuel for star formation, with an estimated quenching time-scale of 4 ± 1 Gyr. G1547 provides a unique perspective into the external mechanisms that could explain the migration of galaxies into the green valley.

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