Related papers: Mid-Infrared Emission from E+A Galaxies in the Com…
We analyse the integrated properties of the Mid-IR emission of a complete, optically selected sample of galaxies in the Virgo cluster observed with the ISOCAM instrument on board the ISO satellite. The analysis shows that the Mid-IR…
(Abridged) We present results of an H-alpha survey in the rich cluster A1689 at z=0.18, using the LDSS++ spectrograph on the AAT. We obtained spectra covering redshifted H-alpha for 522 galaxies brighter than I=22.5, covering a field of…
We present broad-band (U, V, I,and H) and narrow-band(H-alpha+[N II] and Paschen-alpha) images of the circumnuclear starburst rings in two nearby spiral galaxies, NGC 1512 and NGC 5248, obtained with WFPC2 and NICMOS on HST. Combined with…
Star formation in galaxies is observed to be associated with gamma-ray emission. The detection of gamma rays from star-forming galaxies by the Fermi Large Area Telescope (LAT) has allowed the determination of a functional relationship…
High resolution spectra of 110 selected red giant stars in the globular cluster M15 (NGC 7078) were obtained with Hectochelle at the MMT telescope in 2005 May, 2006 May, and 2006 October. Echelle orders containing Halpha and Ca H & K are…
We report a new analysis of diffuse EUV emission in clusters of galaxies. We find the cluster emission is strongly influenced by the variation of the telescope sensitivity over the field of view and upon the details of the subtraction of…
The ages of stellar populations in 52 elliptical and S0 galaxies in the Coma cluster are investigated using a new spectroscopic sample. More than 40% of the S0s are found to have experienced recent star formation in their central regions…
Multiwavelength observations suggest that clusters are reservoirs of vast amounts relativistic electrons and positrons that are either injected into and accelerated directly in the intra-cluster medium, or produced as secondary pairs by…
We make use of Spitzer imaging between 4 and 16 micron and near-infrared data at 2.2 micron to investigate the nature and distribution of the mid-infrared emission in a sample of early-type galaxies in the Virgo cluster. These data allow us…
We cross-matched Wide-field Infrared Survey Explorer (WISE) sources brighter than 1 mJy at 12um with the Sloan Digital Sky Survey (SDSS) galaxy spectroscopic catalog to produce a sample of ~10^5 galaxies at <z>=0.08, the largest of its…
The Infrared Space Observatory was used to search for a tracer of the warm and dense neutral interstellar medium, the [O I] 63.18 micron line, in four ultraluminous IRAS sources lying at redshifts between 0.6 and 1.4. While these sources…
Although the existence of a faint background of starlight in the core of the Coma cluster has been well established (1,2), its origin is uncertain. This vast sea of stars could have formed outside the galaxies, using gas left over from the…
The central galaxies of some clusters can be strong emitters in the Ly$\alpha$ and H$\alpha$ lines. This emission may arise either from the cool/warm gas located in the cool core of the cluster or from the bright AGN within the central…
Galaxy clusters can be sources of high-energy (HE) $\gamma$-ray radiation, due to the efficient acceleration of particles exceeding EeV energies. At present, though, the only candidate for emitting HE $\gamma$-rays is the Coma cluster,…
The radio luminosities at 1.4 GHz is tightly correlated with the far-infrared luminosities for various galaxy types (e.g. [16, 6, 2]) over a wide range of redshift (see e.g. [5, 1, 15, 8, 7]). The relationship is widely believed to be…
We present line-strength measurements for 74 early-type galaxies in the core of the Coma cluster reaching down to velocity dispersions, sigma, of 30 km/s. The index-sigma relations for our sample, including galaxies with sigma<100 km/s…
In an earlier paper, we determined the morphological types of galaxies in the Coma Cluster using data from the HST/ACS Coma Cluster treasury survey. We found that of the 132 members, 51 are non dwarfs and 81 are dwarfs. We define dwarfs to…
We report the cumulative results of an on-going near-infrared search for redshifted H-alpha emission from normal galaxies at z>2. An infrared search reduces the bias due to reddening. Using narrow-band imaging with the Near Infrared Camera…
We present near-infrared spectra for a sample of galaxies with ambiguous optical emission line ratios. These galaxies fall between starbursts and Seyferts in the usual optical diagnostic diagrams. We find a similar result with the…
We study the infrared (IR) properties of galaxies in the cluster MS 1054-03 at z=0.83 by combining MIPS 24 micron data with spectra of more than 400 galaxies and a very deep K-band selected catalog. 19 IR cluster members are selected…