ﻻ يوجد ملخص باللغة العربية
We investigate the role of dense Mpc-scale environments in processing molecular gas of cluster galaxies as they fall into the cluster cores. We consider $sim20$ luminous infrared galaxies (LIRGs) in intermediate-$z$ clusters, from the Hershel Lensing Survey and the Local Cluster Substructure Survey. They include MACS J0717.5+3745 at $z=0.546$ and Abell 697, 963, 1763, and 2219 at $z=0.2-0.3$. We have performed far infrared to ultraviolet spectral energy distribution modeling of the LIRGs, which span cluster-centric distances within $r/r_{200}simeq0.2-1.6$. We have observed the LIRGs in CO(1$rightarrow$0) or CO(2$rightarrow$1) with the Plateau de Bure interferometer and its successor NOEMA, as part of five observational programs carried out between 2012 and 2017. We have compared the molecular gas to stellar mass ratio $M(H_2)/M_star$, star formation rate (SFR), and depletion time ($tau_{rm dep}$) of the LIRGs with those of a compilation of cluster and field star forming galaxies. The targeted LIRGs have SFR, $M(H_2)/M_star$, and $tau_{rm dep}$ that are consistent with those of both main sequence (MS) field galaxies and star forming galaxies from the comparison sample. However we find that the depletion time, normalized to the MS value, increases with increasing $r/r_{200}$, with a significance of $2.8sigma$, which is ultimately due to a deficit of cluster core LIRGs with $tau_{rm dep}gtrsimtau_{rm dep,MS}$. We suggest that a rapid exhaustion of the molecular gas reservoirs occurs in the cluster LIRGs and is effective in suppressing their star formation. This mechanism may explain the exponential decrease of the fraction of cluster LIRGs with cosmic time. The compression of the gas in LIRGs, possibly induced by intra-cluster medium shocks, may be responsible for the short depletion timescales, observed in a large fraction of cluster core LIRGs.
We present the detection of molecular gas using CO(1-0) line emission and follow up Halpha imaging observations of galaxies located in nearby voids. The CO(1-0) observations were done using the 45m telescope of the Nobeyama Radio Observatory (NRO) an
Collisions were suggested to potentially play a role in the formation of massive stars in present day clusters, and have likely been relevant during the formation of massive stars and intermediate mass black holes within the first star clusters. In t
Aims. We present a spectroscopic study of the properties of 64 Balmer break galaxies that show signs of star formation. The studied sample of star-forming galaxies spans a redshift range from 0.094 to 1.475 with stellar masses in the range 10$^{8}-$1
We use observations of chlorine-bearing species in molecular absorbers at intermediate redshifts to investigate chemical properties and $^{35}$Cl/$^{37}$Cl isotopic ratios in the absorbing sightlines. Chloronium (H$_2$Cl$^+$) is detected along three
Atacama Large Millimeter/submillimeter Array (ALMA) 12CO(J=1-0) observations are used to study the cold molecular ISM of the Cartwheel ring galaxy and its relation to HI and massive star formation (SF). CO moment maps find $(2.69pm0.05)times10^{9}$ M