scholarly journals Dwarf galaxies as hosts of stellar explosions: gas kinematics and abundances in 3D

2018 ◽  
Vol 14 (S344) ◽  
pp. 224-227
Author(s):  
C. C. Thöne ◽  
L. Izzo ◽  
H. Flores ◽  
S. Vergani ◽  
L. Christensen
Keyword(s):  
Star Formation ◽  
Gamma Ray ◽  
High Spectral Resolution ◽  
Narrow Component ◽  
Star Forming ◽  
Gas Kinematics ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Excess Emission ◽  
Show Evidence

AbstractThe hosts of long Gamma-ray bursts (GRBs) are places of intense star-formation, which, at low redshift, are primarily low-mass dwarf starburst galaxies. Spatially resolved studies of these galaxies are still sparse, even more so at high spectral resolution where we can probe gas kinematics, in- and outflows and differences in abundance between different components. Here we present the first high resolution IFU sample of six low redshift GRB hosts, all dwarf starbursts. All galaxies in our sample show evidence for excess emission or broad emission components, with velocities of 100-200 km s−1. For GRB 030329, outflowing gas had also been observed in absorption in spectra of the GRB afterglow. The high velocity emission is usually blue shifted, connected to the brightest star-forming regions and more metal rich than the narrow component associated with the emission of the general host ISM. This gives strong indications that the excess emission/broad component is indeed associated to a starburst wind as observed in many field star-burst galaxies and a sign for the intense ongoing star-formation in those galaxies.

scholarly journals Blowin' in the wind: both ‘negative’ and ‘positive’ feedback in an outflowing quasar at z∼1.6

2014 ◽  
Vol 10 (S309) ◽  
pp. 239-242
Author(s):  
Giovanni Cresci
Keyword(s):  
Star Formation ◽  
Positive Feedback ◽  
Near Infrared ◽  
Host Galaxy ◽  
Narrow Component ◽  
Massive Galaxies ◽  
Star Forming ◽  
Star Forming Regions ◽  
Integral Field Spectroscopy ◽  
Outflow Rate

AbstractQuasar feedback in the form of powerful outflows is invoked as a key mechanism to quench star formation, preventing massive galaxies to over-grow and producing the red colors of ellipticals. On the other hand, some models are also requiring ‘positive’ AGN feedback, inducing star formation in the host galaxy through enhanced gas pressure in the interstellar medium. However, finding observational evidence of the effects of both types of feedback is still one of the main challenges of extragalactic astronomy, as few observations of energetic and extended radiatively-driven winds are available. We present SINFONI near infrared integral field spectroscopy of XID2028, an obscured, radio-quiet z=1.59 QSO, in which we clearly resolve a fast (1500 km/s) and extended (up to 13 kpc from the black hole) outflow in the [OIII] lines emitting gas, whose large velocity and outflow rate are not sustainable by star formation only. The narrow component of Hα emission and the rest frame U band flux show that the outflow position lies in the center of an empty cavity surrounded by star forming regions on its edge. The outflow is therefore removing the gas from the host galaxy (‘negative feedback’), but also triggering star formation by outflow induced pressure at the edges (‘positive feedback’). XID2028 represents the first example of a host galaxy showing both types of feedback simultaneously at work.

scholarly journals Star formation on galactic scales

2006 ◽  
Vol 2 (S237) ◽  
pp. 311-316
Author(s):  
Robert C. Kennicutt
Keyword(s):  
Star Formation ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Multi Wavelength ◽  
Nearby Galaxies

AbstractNew multi-wavelength data on nearby galaxies are providing a much more accurate and complete observational picture of star formation on galactic scales. Here I briefly report on recent results from the Spitzer Infrared Nearby Galaxies Survey (SINGS). These provide new constraints on the frequency and lifetime of deeply obscured star-forming regions in galaxies, the measurement of dust-corrected star formation rates in galaxies, and the form of the spatially-resolved Schmidt law.

scholarly journals The host galaxy of GRB 980425/SN1998bw: a collisional ring galaxy

2019 ◽  
Vol 485 (4) ◽  
pp. 5411-5422 ◽  
Author(s):  
M Arabsalmani ◽  
S Roychowdhury ◽  
T K Starkenburg ◽  
L Christensen ◽  
E Le Floc’h ◽  
...  
Keyword(s):  
Star Formation ◽  
Gamma Ray ◽  
Dwarf Galaxy ◽  
Formation Rate ◽  
Host Galaxy ◽  
Gamma Ray Burst ◽  
Star Forming ◽  
Star Forming Regions ◽  
Very Large Telescope ◽  
Companion Galaxy

ABSTRACT We report Giant Metrewave Radio Telescope (GMRT), Very Large Telescope (VLT), and Spitzer Space Telescope observations of ESO 184−G82, the host galaxy of GRB 980425/SN 1998bw, that yield evidence of a companion dwarf galaxy at a projected distance of 13 kpc. The companion, hereafter GALJ193510-524947, is a gas-rich, star-forming galaxy with a star formation rate of $\rm 0.004\, M_{\odot }\, yr^{-1}$, a gas mass of $10^{7.1\pm 0.1} \, \mathrm{M}_{\odot}$, and a stellar mass of $10^{7.0\pm 0.3} \, \mathrm{M}_{\odot}$. The interaction between ESO 184−G82 and GALJ193510-524947 is evident from the extended gaseous structure between the two galaxies in the GMRT H i 21 cm map. We find a ring of high column density H i gas, passing through the actively star-forming regions of ESO 184−G82 and the GRB location. This ring lends support to the picture in which ESO 184−G82 is interacting with GALJ193510-524947. The massive stars in GALJ193510-524947 have similar ages to those in star-forming regions in ESO 184−G82, also suggesting that the interaction may have triggered star formation in both galaxies. The gas and star formation properties of ESO 184−G82 favour a head-on collision with GALJ193510-524947 rather than a classical tidal interaction. We perform state-of-the-art simulations of dwarf–dwarf mergers and confirm that the observed properties of ESO 184−G82 can be reproduced by collision with a small companion galaxy. This is a very clear case of interaction in a gamma-ray burst host galaxy and of interaction-driven star formation giving rise to a gamma-ray burst in a dense environment.

scholarly journals The Spatially-Resolved Star Formation History of the M31 Disk from Resolved Stellar Populations

2014 ◽  
Vol 10 (S309) ◽  
pp. 57-60
Author(s):  
Alexia R. Lewis ◽  
Julianne J. Dalcanton ◽  
Andrew E. Dolphin ◽  
Daniel R. Weisz ◽  
Benjamin F. Williams ◽  
...  
Keyword(s):  
Star Formation ◽  
Stellar Populations ◽  
Star Formation History ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Star Formation Activity ◽  
Individual Star ◽  
Star Formation Histories ◽  
Optical Color

AbstractThe Panchromatic Hubble Andromeda Treasury (PHAT) is an HST multi-cycle treasury program that has mapped the resolved stellar populations of ∼1/3 of the disk of M31 from the UV through the near-IR. This data provides color and luminosity information for more than 150 million stars. Using stellar evolution models, we model the optical color-magnitude diagram to derive spatially-resolved recent star formation histories (SFHs) over large areas of M31 with 100 pc resolution. These include individual star-forming regions as well as quiescent portions of the disk. With these gridded SFHs, we create movies of star formation activity to study the evolution of individual star-forming events across the disk. We analyze the structure of star formation and examine the relation between star formation and gas throughout the disk and particularly in the 10-kpc star-forming ring. We find that the ring has been continuously forming stars for at least 500 Myr. As the only large disk galaxy that is close enough to obtain the photometry for this type of spatially-resolved SFH mapping, M31 plays an important role in our understanding of the evolution of an L* galaxy.

Gamma-ray burst models

2007 ◽  
Vol 365 (1854) ◽  
pp. 1277-1280 ◽  
Author(s):  
Andrew King
Keyword(s):  
Black Hole ◽  
Star Formation ◽  
Neutron Star ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Close Binaries ◽  
Host Galaxy ◽  
Star Forming ◽  
Star Forming Regions ◽  
Long Duration

I consider various possibilities for making gamma-ray bursts, particularly from close binaries. In addition to the much-studied neutron star+neutron star and black hole+neutron star cases usually considered good candidates for short-duration bursts, there are also other possibilities. In particular, neutron star+massive white dwarf has several desirable features. These systems are likely to produce long-duration gamma-ray bursts (GRBs), in some cases definitely without an accompanying supernova, as observed recently. This class of burst would have a strong correlation with star formation and occur close to the host galaxy. However, rare members of the class need not be near star-forming regions and could have any type of host galaxy. Thus, a long-duration burst far from any star-forming region would also be a signature of this class. Estimates based on the existence of a known progenitor suggest that this type of GRB may be quite common, in agreement with the fact that the absence of a supernova can only be established in nearby bursts.

scholarly journals The [C ii]–SFR correlation in dwarf galaxies across cosmic time

2020 ◽  
Vol 492 (2) ◽  
pp. 2818-2827 ◽  
Author(s):  
Alessandro Lupi ◽  
Stefano Bovino
Keyword(s):  
Star Formation ◽  
Dwarf Galaxy ◽  
Formation Rate ◽  
Cosmic Time ◽  
Theoretical Models ◽  
Large Scatter ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Neutral Gas

ABSTRACT Current galaxy observations suggest that a roughly linear correlation exists between the [C ii] emission and the star formation rate, either as spatially resolved or integrated quantities. Observationally, this correlation seems to be independent of metallicity, but the very large scatter does not allow to properly assess whether this is true. On the other hand, theoretical models tend to suggest a metallicity dependence of the correlation. In this study, we investigate the metallicity evolution of the correlation via a high-resolution zoom-in cosmological simulation of a dwarf galaxy employing state-of-the-art sub-grid modelling for gas cooling, star formation, and stellar feedback, and that self-consistently evolves the abundances of metal elements out of equilibrium. Our results suggest that the correlation should evolve with metallicity, in agreement with theoretical predictions, but also that this evolution can be hardly detected in observations, because of the large scatter. We also find that most of the [C ii] emission is associated with neutral gas at low-intermediate densities, whereas the highest emissivity is produced by the densest regions around star-forming regions.

scholarly journals What drives galaxy quenching? Resolving molecular gas and star formation in the green valley

2020 ◽  
Vol 498 (1) ◽  
pp. L66-L71 ◽  
Author(s):  
Simcha Brownson ◽  
Francesco Belfiore ◽  
Roberto Maiolino ◽  
Lihwai Lin ◽  
Stefano Carniani
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Gas Content ◽  
Molecular Gas ◽  
Data Sets ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Central Regions

ABSTRACT We study quenching in seven green valley galaxies on kpc scales by resolving their molecular gas content using 12CO(1–0) observations obtained with NOrthern Extended Millimeter Array and Atacama Large Millimeter Array, and their star formation rate using spatially resolved optical spectroscopy from the Mapping Nearby Galaxies at Apache Point Observatory survey. We perform radial stacking of both data sets to increase the sensitivity to molecular gas and star formation, thereby avoiding biases against strongly quenched regions. We find that both spatially resolved gas fraction (fgas) and star formation efficiency ($\rm {SFE}$) are responsible for quenching green valley galaxies at all radii: both quantities are suppressed with respect to typical star-forming regions. fgas and $\rm {SFE}$ have roughly equal influence in quenching the outer disc. We are, however, unable to identify the dominant mechanism in the strongly quenched central regions. We find that fgas is reduced by $\rm \sim\! 1~dex$ in the central regions, but the star formation rate is too low to be measured, leading to upper limits for the $\rm {SFE}$. Moving from the outer disc to central regions, the reduction in fgas is driven by an increasing $\rm \Sigma _{\star }$ profile rather than a decreasing $\rm \Sigma _{H_{2}}$ profile. The reduced fgas may therefore be caused by a decrease in the gas supply rather than molecular gas ejection mechanisms, such as winds driven by active galactic nuclei. We warn more generally that studies investigating fgas may be deceiving in inferring the cause of quenching, particularly in the central (bulge-dominated) regions of galaxies.

scholarly journals Molecular cloud structure and star formation in the W43 complex

2012 ◽  
Vol 10 (H16) ◽  
pp. 592-592
Author(s):  
P. Carlhoff ◽  
P. Schilke ◽  
F. Motte ◽  
Q. Nguyen Luong
Keyword(s):  
Star Formation ◽  
Spectral Resolution ◽  
Total Mass ◽  
Column Density ◽  
Massive Star ◽  
High Spectral Resolution ◽  
Excitation Temperature ◽  
Star Forming ◽  
Star Forming Regions ◽  
Different Sources

AbstractThe W43 region is one of the most massive star forming regions in our Galaxy. It is subject to a large IRAM 30m project that observes high spectral resolution maps of the complete complex in the 13CO (2–1) and C18O (2–1) lines. We find a variety of different sources of which we calculate excitation temperature, H2 column density and mass. We find the total mass of dense clouds in the complex to be 1.2×106 M⊙.

scholarly journals Resolved galactic superwinds reconstructed around their host galaxies at z > 3

2021 ◽  
Vol 504 (2) ◽  
pp. 2629-2657
Author(s):  
Mandy C Chen ◽  
Hsiao-Wen Chen ◽  
Max Gronke ◽  
Michael Rauch ◽  
Tom Broadhurst
Keyword(s):  
Imaging Spectroscopy ◽  
Resonant Scattering ◽  
Spatial Variations ◽  
Host Galaxies ◽  
Star Forming ◽  
Lyman Alpha ◽  
Gas Kinematics ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
Low Mass

ABSTRACT This paper presents a detailed analysis of two giant Lyman-alpha (Ly α) arcs detected near galaxies at z = 3.038 and z = 3.754 lensed by the massive cluster MACS 1206−0847 (z = 0.44). The Ly α nebulae revealed in deep MUSE observations exhibit a double-peaked profile with a dominant red peak, indicating expansion/outflowing motions. One of the arcs stretches over 1 arcmin around the cluster Einstein radius, resolving the velocity field of the line-emitting gas on kpc scales around three star-forming galaxies of 0.3–$1.6\, L_*$ at z = 3.038. The second arc spans 15 arcsec in size, roughly centred around two low-mass Ly α emitters of $\approx 0.03\, L_*$ at z = 3.754. All three galaxies in the z = 3.038 group exhibit prominent damped Ly α absorption (DLA) and several metal absorption lines, in addition to nebular emission lines such as $\hbox{He ii}$$\lambda \, 1640$ and C iii]λλ1906, 1908. Extended Ly α emission appears to emerge from star-forming regions with suppressed surface brightness at the centre of each galaxy. Significant spatial variations in the Ly α line profile are observed which, when unaccounted for in the integrated line, leads to biased constraints for the underlying gas kinematics. The observed spatial variations indicate the presence of a steep velocity gradient in a continuous flow of high column density gas from star-forming regions into a low-density halo environment. A detailed inspection of available galaxy spectra shows no evidence of AGN activity in the galaxies, and the observed Ly α signals are primarily explained by resonant scattering. The study presented in this paper shows that spatially resolved imaging spectroscopy provides the most detailed insights yet into the kinematics of galactic superwinds associated with star-forming galaxies.

scholarly journals Using stellar population studies to determine the progenitors of GRBs and SNe

2009 ◽  
Vol 5 (S262) ◽  
pp. 436-437
Author(s):  
Christina C. Thöne ◽  
Lise Christensen ◽  
Johan P. U. Fynbo
Keyword(s):  
Emission Line ◽  
Stellar Population ◽  
Population Studies ◽  
Population Models ◽  
Host Galaxy ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions

AbstractWe present spatially resolved emission line studies of three nearby GRB and SN hosts with longslit and/or IFU observations. We compare the environment of the GRBs/SNe with those of other star-forming regions in the host galaxy and try to get informations on the progenitor from stellar population models and metallicities.

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