scholarly journals Molecular gas mass functions of normal star-forming galaxies sincez ~  3

2013 ◽  
Vol 555 ◽  
pp. L8 ◽  
Author(s):  
S. Berta ◽  
D. Lutz ◽  
R. Nordon ◽  
R. Genzel ◽  
B. Magnelli ◽  
...  
Keyword(s):  
Molecular Gas ◽  
Star Forming ◽  
Normal Star ◽  
Mass Functions

scholarly journals Spatially resolved molecular gas properties of host galaxy of Type I superluminous supernova SN 2017egm

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Bunyo Hatsukade ◽  
Kana Morokuma-Matsui ◽  
Masao Hayashi ◽  
Nozomu Tominaga ◽  
Yoichi Tamura ◽  
...  
Keyword(s):  
Star Formation ◽  
Column Density ◽  
Formation Rate ◽  
Host Galaxy ◽  
Molecular Gas ◽  
Type I ◽  
Type Ii ◽  
Star Forming ◽  
Spatially Resolved ◽  
Normal Star

Abstract We present the results of CO(1–0) observations of the host galaxy of a Type I superluminous supernova (SLSN-I), SN 2017egm, one of the closest SLSNe-I at z = 0.03063, by using the Atacama Large Millimeter/submillimeter Array. The molecular gas mass of the host galaxy is Mgas = (4.8 ± 0.3) × 109 M⊙, placing it on the sequence of normal star-forming galaxies in an Mgas–star-formation rate (SFR) plane. The molecular hydrogen column density at the location of SN 2017egm is higher than that of the Type II SN PTF10bgl, which is also located in the same host galaxy, and those of other Type II and Ia SNe located in different galaxies, suggesting that SLSNe-I have a preference for a dense molecular gas environment. On the other hand, the column density at the location of SN 2017egm is comparable to those of Type Ibc SNe. The surface densities of molecular gas and the SFR at the location of SN 2017egm are consistent with those of spatially resolved local star-forming galaxies and follow the Schmidt–Kennicutt relation. These facts suggest that SLSNe-I can occur in environments with the same star-formation mechanism as in normal star-forming galaxies.

scholarly journals Automated mining of the ALMA archive in the COSMOS field (A3 COSMOS): Cold molecular gas evolution

2019 ◽  
Vol 15 (S352) ◽  
pp. 228-233
Author(s):  
Liu Daizhong ◽  
Keyword(s):  
Main Sequence ◽  
Stellar Mass ◽  
Molecular Gas ◽  
Gas Evolution ◽  
Field Surveys ◽  
Star Forming ◽  
The Public ◽  
Multi Wavelength ◽  
Mass Functions ◽  
Coherent Picture

AbstractWe present new constraints on the cosmic cold molecular gas evolution out to redshift 6 based on systematic mining of the public ALMA archive in the COSMOS field (A3 COSMOS). Our A3 COSMOS dataset contains ∼ 700 galaxies (0.3 ≲ z ≲ 6) with high-confidence ALMA detection and multi-wavelength SEDs. Combining with ∼ 1,200 CO-observed galaxies at 0 ≲ z ≲ 4 (75% at z < 0.1) in the literature, we parameterize galaxies’ molecular gas depletion time and gas fraction each as a function of stellar mass, offset from the star-forming main-sequence and cosmic age. We propose a new functional form which provides a better fit and implies a “downsizing” effect and “mass-quenching”. By adopting galaxy stellar mass functions and applying our gas fraction function, we obtain a cosmic cold molecular gas density evolution in agreement with recent CO blind field surveys as well as semi-analytic modeling. These together provide us a coherent picture of galaxy cold molecular gas, SFR and stellar mass evolution.

scholarly journals Molecular gas content in obscured AGN at z > 1

2018 ◽  
Vol 619 ◽  
pp. A90 ◽  
Author(s):  
M. Perna ◽  
M. T. Sargent ◽  
M. Brusa ◽  
E. Daddi ◽  
C. Feruglio ◽  
...  
Keyword(s):  
Gas Content ◽  
Host Galaxy ◽  
Molecular Gas ◽  
Evolutionary Sequence ◽  
Gas Reservoir ◽  
Complete Collection ◽  
Star Forming ◽  
Normal Star ◽  
Black Hole Growth ◽  
Hole Growth

Aims. The standard active galactic nuclei (AGN)-galaxy co-evolutionary scenario predicts a phase of deeply “buried” supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous quasar (QSO) is revealed (called the SB-QSO evolutionary sequence). The aim of this work is to measure the cold gas reservoir of three highly obscured QSOs to test if their gas fraction is similar to that of submillimetre galaxies (SMGs), as expected by some models, and to place these measurements in the context of the SB-QSO framework. Methods. We target CO(1-0) transition in BzK4892, a Compton thick (CT) QSO at z = 2.6, CO(1-0) in BzK8608 and CO(2-1) in CDF153, two highly obscured (NH ≈ 6 × 1023 cm−2) QSOs at z = 2.5 and z = 1.5, respectively. For these targets, we place 3σ upper limits on the CO lines, with L′CO < (1.5 ÷ 2.8)×1010 K km s−1 pc2. We also compare the molecular gas conditions of our targets with those of other systems at z > 1, considering normal star-forming galaxies and SMGs, and unobscured and obscured AGN from the literature. For the AGN samples, we provide an updated and almost complete collection of targets with CO follow-up at z > 1. Results. BzK4892 displays a high star formation efficiency (SFE = LIR/L′CO > 410 L⊙/(K km s−1 pc2 )) and a gas fraction fgas = Mgas/(Mstar + Mgas)< 10%. Less stringent constraints are derived for the other two targets (fgas < 0.5 and SFE > 10 L⊙/(K km s−1 pc2 )). From the comparison with the literature data we found that, on average, i) obscured AGN at z > 1 are associated with higher SFE and lower fgas with respect to normal star-forming galaxies and SMGs; ii) mildly and highly obscured active galaxies have comparable gas fractions; iii) the SFE of CT and obscured AGN are similar to those of unobscured AGN. Conclusions. Within the SB-QSO framework, these findings could be consistent with a scenario where feedback can impact the host galaxy already from the early phases of the SB-QSO evolutionary sequence.

scholarly journals ALMA detects molecular gas in the halo of the powerful radio galaxy TXS 0828+193

2020 ◽  
Author(s):  
Judit Fogasy ◽  
K K Knudsen ◽  
G Drouart ◽  
B Gullberg
Keyword(s):  
Large Scale ◽  
High Redshift ◽  
Molecular Gas ◽  
Filamentary Structure ◽  
Massive Galaxies ◽  
Star Forming ◽  
Normal Star ◽  
The Universe ◽  
Co Emission ◽  
Powerful Radio Galaxy

Abstract Both theoretical and observational results suggest that high-redshift radio galaxies (HzRGs) inhabit overdense regions of the universe and might be the progenitors of local, massive galaxies residing in the centre of galaxy clusters. In this paper we present CO(3–2) line observations of the HzRG TXS 0828+193 (z = 2.57) and its environment using the Atacama Large Millimeter/submillimeter Array. In contrast to previous observations, we detect CO emission associated with the HzRG and derive a molecular gas mass of $(0.9\pm 0.3)\times 10^{10}\, \rm M_{\odot }$. Moreover, we confirm the presence of a previously detected off-source CO emitting region (companion #1), and detect three new potential companions. The molecular gas mass of each companion is comparable to that of the HzRG. Companion #1 is aligned with the axis of the radio jet and has stellar emission detected by Spitzer. Thus this source might be a normal star-forming galaxy or alternatively a result of jet-induced star formation. The newly found CO sources do not have counterparts in any other observing band and could be high-density clouds in the halo of TXS 0828+193 and thus potentially linked to the large-scale filamentary structure of the cosmic web.

Cold gas studies of a z = 2.5 protocluster

2020 ◽  
Vol 15 (S359) ◽  
pp. 136-140
Author(s):  
Minju M. Lee ◽  
Ichi Tanaka ◽  
Rohei Kawabe
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Kinematic Model ◽  
Molecular Gas ◽  
General View ◽  
Massive Galaxies ◽  
Star Forming ◽  
Gas Kinematics ◽  
Narrow Band Filter ◽  
Stellar Masses

AbstractWe present studies of a protocluster at z =2.5, an overdense region found close to a radio galaxy, 4C 23.56, using ALMA. We observed 1.1 mm continuum, two CO lines (CO (4–3) and CO (3–2)) and the lower atomic carbon line transition ([CI](3P1-3P0)) at a few kpc (0″.3-0″.9) resolution. The primary targets are 25 star-forming galaxies selected as Hα emitters (HAEs) that are identified with a narrow band filter. These are massive galaxies with stellar masses of > 1010Mʘ that are mostly on the galaxy main sequence at z =2.5. We measure the molecular gas mass from the independent gas tracers of 1.1 mm, CO (3–2) and [CI], and investigate the gas kinematics of galaxies from CO (4–3). Molecular gas masses from the different measurements are consistent with each other for detection, with a gas fraction (fgas = Mgas/(Mgas+ Mstar)) of ≃ 0.5 on average but with a caveat. On the other hand, the CO line widths of the protocluster galaxies are typically broader by ˜50% compared to field galaxies, which can be attributed to more frequent, unresolved gas-rich mergers and/or smaller sizes than field galaxies, supported by our high-resolution images and a kinematic model fit of one of the galaxies. We discuss the expected scenario of galaxy evolution in protoclusters at high redshift but future large surveys are needed to get a more general view.

scholarly journals Quenching by gas compression and consumption

2019 ◽  
Vol 624 ◽  
pp. A81 ◽  
Author(s):  
Allison W. S. Man ◽  
Matthew D. Lehnert ◽  
Joël D. R. Vernet ◽  
Carlos De Breuck ◽  
Theresa Falkendal
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Relative Strength ◽  
Star Formation History ◽  
Molecular Gas ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Star Forming ◽  
Gas Compression ◽  
Formation History

The objective of this work is to study how active galactic nuclei (AGN) influence star formation in host galaxies. We present a detailed investigation of the star-formation history and conditions of a z = 2.57 massive radio galaxy based on VLT/X-shooter and ALMA observations. The deep rest-frame ultraviolet spectrum contains photospheric absorption lines and wind features indicating the presence of OB-type stars. The most significantly detected photospheric features are used to characterize the recent star formation: neither instantaneous nor continuous star-formation history is consistent with the relative strength of the Si IIλ1485 and S Vλ1502 absorption. Rather, at least two bursts of star formation took place in the recent past, at 6+1-2 Myr and ≳20 Myr ago, respectively. We deduce a molecular H2 gas mass of (3.9 ± 1.0) × 1010 M⊙ based on ALMA observations of the [C I] 3P2−3P1 emission. The molecular gas mass is only 13% of its stellar mass. Combined with its high star-formation rate of (1020-170+190 M⊙ yr-1, this implies a high star-formation efficiency of (26 ± 8) Gyr−1 and a short depletion time of (38 ± 12) Myr. We attribute the efficient star formation to compressive gas motions in order to explain the modest velocity dispersions (⩽55 km s−1) of the photospheric lines and of the star-forming gas traced by [C I]. Because of the likely very young age of the radio source, our findings suggest that vigorous star formation consumes much of the gas and works in concert with the AGN to remove any residual molecular gas, and eventually quenching star formation in massive galaxies.

scholarly journals Survival of molecular gas in a stellar feedback-driven outflow witnessed with the MUSE TIMER project and ALMA

2019 ◽  
Vol 488 (3) ◽  
pp. 3904-3928 ◽  
Author(s):  
Ryan Leaman ◽  
Francesca Fragkoudi ◽  
Miguel Querejeta ◽  
Gigi Y C Leung ◽  
Dimitri A Gadotti ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Mechanical Energy ◽  
Molecular Gas ◽  
Ionized Gas ◽  
Star Forming ◽  
Stellar Feedback ◽  
Dominant Component ◽  
The Galaxy ◽  
Field Lines

ABSTRACT Stellar feedback plays a significant role in modulating star formation, redistributing metals, and shaping the baryonic and dark structure of galaxies – however, the efficiency of its energy deposition to the interstellar medium is challenging to constrain observationally. Here we leverage HST and ALMA imaging of a molecular gas and dust shell ($M_{\mathrm{ H}_2} \sim 2\times 10^{5}\, {\rm M}_{\odot }$) in an outflow from the nuclear star-forming ring of the galaxy NGC 3351, to serve as a boundary condition for a dynamical and energetic analysis of the outflowing ionized gas seen in our MUSE TIMER survey. We use starburst99 models and prescriptions for feedback from simulations to demonstrate that the observed star formation energetics can reproduce the ionized and molecular gas dynamics – provided a dominant component of the momentum injection comes from direct photon pressure from young stars, on top of supernovae, photoionization heating, and stellar winds. The mechanical energy budget from these sources is comparable to low luminosity active galactic neuclei, suggesting that stellar feedback can be a relevant driver of bulk gas motions in galaxy centres – although here ≲10−3 of the ionized gas mass is escaping the galaxy. We test several scenarios for the survival/formation of the cold gas in the outflow, including in situ condensation and cooling. Interestingly, the geometry of the molecular gas shell, observed magnetic field strengths and emission line diagnostics are consistent with a scenario where magnetic field lines aided survival of the dusty ISM as it was initially launched (with mass-loading factor ≲1) from the ring by stellar feedback. This system’s unique feedback-driven morphology can hopefully serve as a useful litmus test for feedback prescriptions in magnetohydrodynamical galaxy simulations.

scholarly journals PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS INz∼ 1-3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES

2013 ◽  
Vol 768 (1) ◽  
pp. 74 ◽  
Author(s):  
L. J. Tacconi ◽  
R. Neri ◽  
R. Genzel ◽  
F. Combes ◽  
A. Bolatto ◽  
...  
Keyword(s):  
Main Sequence ◽  
Gas Content ◽  
Main Sequence Star ◽  
Scaling Relations ◽  
Molecular Gas ◽  
Star Forming

scholarly journals The Connection between Molecular Gas and Star Formation in XUV Disks

2016 ◽  
Vol 11 (S321) ◽  
pp. 214-216
Author(s):  
Linda C. Watson
Keyword(s):  
Star Formation ◽  
Molecular Hydrogen ◽  
Optical Disk ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions

AbstractWe found that star-forming regions in extended ultraviolet (XUV) disks are generally consistent with the molecular-hydrogen Kennicutt-Schmidt law that applies within the inner, optical disk. This is true for star formation rates based on Hα + 24 μm data or FUV + 24 μm data. We estimated that the star-forming regions have ages of 1 − 7 Myr and propose that the presence or absence of molecular gas provides an additional “clock” that may help distinguish between aging and stochasticity as the explanation for the low Hα-to-FUV flux ratios in XUV disks. This contribution is a summary of the work originally presented in Watson et al. (2016).

scholarly journals Shocked Molecular Hydrogen from Star Forming Regions

1987 ◽  
Vol 115 ◽  
pp. 181-181 ◽  
Author(s):  
Adair P. Lane ◽  
John Bally
Keyword(s):  
Shock Waves ◽  
High Velocity ◽  
Molecular Hydrogen ◽  
Near Infrared ◽  
Young Stars ◽  
Emission Lines ◽  
Molecular Gas ◽  
Star Forming ◽  
Star Forming Regions ◽  
Post Shock

Near infrared (2 micron) emission lines from molecular hydrogen provide a powerful probe of the morphology and energetics of outflows associated with stellar birth. The H2 emission regions trace the location of shock waves formed when the high velocity outflow from young stars encounters dense quiescent gas. Since H2 is the dominant coolant of the hot post-shock molecular gas, the H2 lines provide a measure of the fraction of the total mechanical luminosity radiated away from the cloud.

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