arXiv subjects

J. M. Mazzarella

Publications and source records attributed to J. M. Mazzarella.

44 records · Page 3Linked to original sources

arXiv2004

An IRAS High Resolution Image Restoration (HIRES) Atlas of All Interacting Galaxies in the IRAS Revised Bright Galaxy Sample

We present high-resolution (30"-1') 12, 25, 60, and 100 micron images of 106 interacting galaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS, Sanders et al. 2003), a complete sample of all galaxies having a 60 micron flux density greater than 5.24 Jy. These systems were selected to have at least two distinguishable galaxies separated by less than three average galactic diameters, and thus we have excluded very widely separated systems and very advanced mergers. The new complete survey has the same properties as the prototype survey of Surace et al. 1993. We find no increased tendency for infrared-bright galaxies to be associated with other infrared bright galaxies among the widely separated pairs studied here. We find small enhancements in far-infrared activity in multiple galaxy systems relative to RBGS non-interacting galaxies with the same blue luminosity distribution. We also find no differences in infrared activity (as measured by infrared color and luminosity) between late and early-type spiral galaxies.

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arXiv2003

The IRAS Revised Bright Galaxy Sample (RBGS)

IRAS flux densities, redshifts, and infrared luminosities are reported for all sources identified in the IRAS Revised Bright Galaxy Sample (RBGS), a complete flux-limited survey of all extragalactic objects with total 60 micron flux density greater than 5.24 Jy, covering the entire sky surveyed by IRAS at Galactic latitude |b| > 5 degrees. The RBGS includes 629 objects, with a median (mean) sample redshift of 0.0082 (0.0126) and a maximum redshift of 0.0876. The RBGS supersedes the previous two-part IRAS Bright Galaxy Samples, which were compiled before the final ("Pass 3") calibration of the IRAS Level 1 Archive in May 1990. The RBGS also makes use of more accurate and consistent automated methods to measure the flux of objects with extended emission. Basic properties of the RBGS sources are summarized, including estimated total infrared luminosities, as well as updates to cross-identifications with sources from optical galaxy catalogs established using the NASA/IPAC Extragalactic Database (NED). In addition, an atlas of images from the Digitized Sky Survey with overlays of the IRAS position uncertainty ellipse and annotated scale bars is provided for ease in visualizing the optical morphology in context with the angular and metric size of each object. The revised bolometric infrared luminosity function, phi(L_ir), for infrared bright galaxies in the local Universe remains best fit by a double power law, phi(L_ir) ~ L_ir^alpha, with alpha = -0.6 (+/- 0.1), and alpha = -2.2 (+/- 0.1) below and above the "characteristic" infrared luminosity L_ir ~ 10^{10.5} L_solar, respectively. (Abridged)

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arXiv2002

Molecular Gas and Nuclear Activity in Ultraluminous Infrared Galaxies with Double Nuclei

High-resolution CO(1-0) observations of five ultraluminous infrared galaxies (ULIGs: L_IR [8-1000um] >~ 10^12 L_sun) with double nuclei are analyzed. These sources constitute a complete subset of local ULIGs expected to be in an intermediate stage of merging and selected with projected nuclear separations of 2.0-5.4 (3-5 kpc) so they could be resolved with the Owens Valley Radio Observatory Millimeter Array. The observed pairs include two mergers with cool far-infrared colors (25um to 60um flux density ratio f_25um/f_60um < 0.2) from the Infrared Astronomical Satellite (IRAS) Bright Galaxy Sample (IRAS 12112+0305 and IRAS 14348-1447) and three mergers with warm infrared dust temperatures f_25um/f_60um >~ 0.2) selected from the IRAS Warm Galaxy Sample (IRAS 08572+3915, IRAS 13451+1232 = PKS 1345+12, and IRAS 13536+1836 = Mrk 463). These ULIGs are further distinguished by the presence of pairs of active nuclei; among the ten nuclei, nine have Seyfert or LINER classifications and one is unclassified. Molecular gas is detected only on the redder, more radio-luminous nucleus of the warm objects, whereas both nuclei of the cool ULIGs are detected in CO. The inferred molecular gas masses for the detected nuclei are 0.1-1.2x10^10 M_sun, and the undetected nuclei have molecular gas masses at least 1.2--2.8 times less than that of their CO-luminous companions. Upper limits on the extent of the CO emitting regions of each detected nucleus range from 2--4 kpc, which is about 3-6 times smaller than the average effective CO diameter of nearby spiral galaxies...

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arXiv1999

Molecular Gas Distribution in Double-Nucleus Ultraluminous Infrared Galaxies

Millimeter (CO) observations of 5 double-nucleus ultraluminous infrared galaxy (ULIG) mergers are presented. With nuclear separations of 3-5 kpc, these galaxies are in the ``intermediate'' stages of the merger process. A preliminary comparison of the distribution of molecular gas (the likely fuel source for both starbursts and active galactic nuclei: AGN) shows a tendency for molecular gas to be associated with the AGN nucleus of ULIGs with ``warm'', Seyfert-like infrared colors ($f_{25 microns}/f_{60 microns} >~ 0.20) and associated with both stellar nuclei of ULIGs with ``cool'' infrared colors (f_{25 microns} /f_{60 microns} < 0.2). Studies of ULIGs with a wide range of nuclear separations using the high resolution and increased sensitivity of ALMA will provide a larger statistical sample with which the gas distribution, molecular gas masses, and densities can be determined as a function of the evolutionary stage, starburst and AGN activity, and lookback time.

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arXiv1999

The Hosts of Ultraluminous Infrared Galaxies

Complete samples of ultraluminous infrared galaxies have been imaged at R-band and K-band from Mauna Kea. Here we present a preliminary analysis of the host galaxy magnitudes and the 1-D radial profiles for a subset of objects in the IRAS 1-Jy sample of ULIGs (z < 0.3), and compare these properties with recently published data for "low-z" QSOs. ULIGs in the 1-Jy sample reside in luminous hosts, with mean luminosities 2.7L* at K-band (range 0.7-11 L*) and 2.2L* at R-band (range 0.5-9 L*), values that are remarkably similar in the mean and range for the hosts of low-z QSOs. Approximately one-third of ULIGs have single nuclei and radial profiles that are closely approximated by a r{1/4}-law over the inner 2-10 kpc galactocentric radius. These "E-like" hosts have half-light radii, and surface brightness similar to QSO hosts at R-band, but systematically smaller half-light radii than QSOs at K-band.

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arXiv1999

Resolved CO(1-0) Nuclei in IRAS 14348-1447: Evidence for Massive Bulge Progenitors to Ultraluminous Infrared Galaxies

High-resolution, CO(1-0) interferometry of the ultraluminous infrared galaxy IRAS 14348-1447 is presented. The merger system has a molecular gas mass of \~3x10^10 solar masses and a projected nuclear separation of 4.8 kpc (3.5"), making it one of the most molecular gas-rich galaxies known and an ideal candidate for studying the intermediate stages of an ultraluminous merger event. The CO morphology shows two molecular gas components associated with the stellar nuclei of the progenitors, consistent with the idea that the molecular disks are gravitationally bound by the dense bulges of the progenitor galaxies as the interaction proceeds. In contrast, less luminous infrared galaxies observed to date with projected nuclear separations of ~<5 kpc show a dominant CO component between the stellar nuclei. This discrepancy may be an indication that the progenitors of mergers with lower infrared luminosity do not possess massive bulges, and that the gas is stripped during the initial encounter of their progenitors. A comparison of the CO and radio luminosities of the NE and SW component show them to have comparable radio and CO flux ratios of f(NE)/f(SW) ~0.6, possibly indicating that the amount of star-forming molecular gas in the progenitors is correlated with the supernovae rate. The estimate of molecular gas masses of the nuclei and the extent of the radio emission are used to infer that the nuclei of IR 14348-1447 have gas densities comparable to the cores of elliptical galaxies.

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arXiv1999

Molecular Gas in the Powerful Radio Nucleus of the Ultraluminous Infrared Galaxy PKS 1345+12

Millimeter CO(1-0) interferometry and high resolution, Hubble Space Telescope (HST) 1.1, 1.6, and 2.2 micron imaging of the radio compact galaxy PKS 1345+12 are presented. With an infrared luminosity of 2x10^{12} L_sun, PKS 1345+12 is a prime candidate for studying the link between the ultraluminous infrared galaxy phenomenon and radio galaxies. These new observations probe the molecular gas distribution and obscured nuclear regions of PKS 1345+12 and provide morphological support for the idea that the radio activity in powerful radio galaxies is triggered by the merger of gas rich galaxies. Two nuclei separated by 2" (4.0 kpc) are observed in the near-infrared; the extended southeastern nucleus has colors consistent with reddened starlight, and the compact northwestern nucleus has extremely red colors indicative of an optical quasar with a warm dust component. Further, the molecular gas, 3mm continuum, and radio emission are coincident with the redder nucleus, confirming that the northwestern nucleus is the site of the AGN and that the molecular gas is the likely fuel source.

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arXiv1998

Molecular Gas in 3C 293: The First Detection of CO Emission and Absorption in an F-R II Radio Galaxy

The first detection of CO emission in a Fanaroff-Riley Class II (i.e., edge-brightened radio morphology) radio galaxy is presented. Multi- wavelength (0.36-2.17 micron) imaging of 3C 293 shows it to be a disk galaxy with an optical jet or tidal tail extending towards what appears to be a companion galaxy 28 kpc away via a low surface brightness envelope. The molecular gas appears to be distributed in an asymmetric disk rotating around an unresolved continuum source, which is presumably emission from the AGN. A narrow (approx 60 km/s) absorption feature is also observed in the CO spectrum and is coincident with the continuum source. Using the standard CO conversion factor, the molecular gas mass is calculated to be 1.5x10^10 M_sun, several times the molecular gas mass of the Milky Way. The high concentration of molecular gas within the central 3 kpc of 3C 293, combined with the multiwavelength morphological peculiarities, support the idea that the radio activity has been triggered by a gas-rich galaxy-galaxy interaction or merger event.

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