The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The second LAT AGN catalog (2LAC) includes 1017 {gamma}-ray sources located at high Galactic latitudes (|b|>10{deg}) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs. However, some of these are affected by analysis issues and some are associated with multiple AGNs. Consequently, we define a Clean Sample which includes 886 AGNs, comprising 395 BL Lacertae objects (BL Lac objects), 310 flat-spectrum radio quasars (FSRQs), 157 candidate blazars of unknown type (i.e., with broadband blazar characteristics but with no optical spectral measurement yet), 8 misaligned AGNs, 4 narrow-line Seyfert 1 (NLS1s), 10 AGNs of other types, and 2 starburst galaxies. Where possible, the blazars have been further classified based on their spectral energy distributions (SEDs) as archival radio, optical, and X-ray data permit. While almost all FSRQs have a synchrotron-peak frequency <10^14^Hz, about half of the BL Lac objects have a synchrotron-peak frequency >10^15^Hz. The 2LAC represents a significant improvement relative to the first LAT AGN catalog (1LAC), with 52% more associated sources. The full characterization of the newly detected sources will require more broadband data. Various properties, such as {gamma}-ray fluxes and photon power-law spectral indices, redshifts, {gamma}-ray luminosities, variability, and archival radio luminosities and their correlations are presented and discussed for the different blazar classes. The general trends observed in 1LAC are confirmed.
We present data from a moderately deep spectroscopic Schmidt survey (B_lim_=17.5) of "active galaxies" selected by the presence of emission lines in their spectra and/or their UV excess. 92 emission line objects have been found in two adjacent fields (approximately 50deg^2^) in the direction of the southern extension of the Virgo cluster. We give a catalog containing positions, photographic R and B magnitudes, U-R colors, effective diameters, redshifts, equivalent widths and intensity ratios of the [OIII]{lambda}{lambda}4959,5007, H{beta} and [OII]{lambda}3727 emission lines. On these fields, we evaluate the completeness limit of the survey at a pseudo B magnitude values of 15.7. A more elaborate astrophysical analysis will appear in a forthcoming paper.
Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imaging data covering 99.998% of the celestial sphere in the near-infrared J(1.25{mu}m), H(1.65{mu}m), and Ks(2.16{mu}m) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona, and Cerro Tololo, Chile. The 2MASS All-Sky Data Release includes the FITS images covering the entire sky, a Point Source Catalog (PSC) of 471 million sources (Cat. II/242), and the present Extended Source Catalog. The 2MASS Extended Source Catalog contains sources that are extended with respect to the instantaneous PSF, such as galaxies and Galactic nebulae. The algorithms used to create the 2MASX catalog are described by Jarett et al. (2000AJ....119.2498J), and in the 2MASS Explanatory Supplement (accessible from the 2MASS Home Page). Briefly, point/ extended-source discrimination was conducted for each band-merged point-source detection by comparing a variety of radial shape, surface brightness, image moments, and symmetry parameters with characteristic stellar parameters using an oblique decision tree classifier. The classification tests included filters to exclude double and triple stars, which were one of the main contaminants in high source density regions. Stellar parameters were measured empirically as a function of time in each scan to compensate for variations in the atmospheric seeing using the aggregate properties of band-merged point-source extractions. The catalog contains 389 columns described briefly in the "Byte-by-byte Description" section below; their description includes also the 2MASS database original column names used in the original descriptions.
The mass function of supermassive black holes in our cosmic neighborhood is required to understand the statistics of their activity and consequently the origin of ultra high energy particles. We determine a mass function of supermassive black hole candidates from the entire sky except for the Galactic plane. Using the 2MASS catalogue as a starting point, and the well-established correlation between black hole mass and the bulge of old population of stars, we derive a list of nearby black hole candidates within the redshift range z<0.025, then perform an additional selection based on the Hubble type. We present our resulting catalogue elsewhere. The final list of black hole candidates above a mass of M_BH_>3x10^6^M_{sun}_ has 5829 entries. We perform a Hubble-type correction to account for selection effects, which reduces this number to 2919 black hole candidates. Here we use this catalogue to derive the black-hole mass function. We also correct for volume, so that this mass function is a volume-limited distribution to redshift 0.025. The differential mass function of nearby black hole candidates is a curved function, with a straight simple power-law of index -3 above 10^8^M_{sun}_ that becomes progressively flatter towards lower masses, turns off towards a gap below 3x10^6^M_{sun}_, and then extends into the range where nuclear star clusters replace black holes. The shape of this mass function can be explained in a simple merger picture. Integrating this mass function over the redshift range for which it has been derived, infers a total number of black holes with z<0.025, and M_BH_>10^7^M_{sun}_ of about 2.4x10^4^, or, if we average uniformly, 0.6 for every square degree on the sky.
Massive early-type galaxies represent the modern day remnants of the earliest major star formation episodes in the history of the universe. These galaxies are central to our understanding of the evolution of cosmic structure, stellar populations, and supermassive black holes, but the details of their complex formation histories remain uncertain. To address this situation, we have initiated the MASSIVE Survey, a volume-limited, multi-wavelength, integral-field spectroscopic (IFS) and photometric survey of the structure and dynamics of the ~100 most massive early-type galaxies within a distance of 108 Mpc. This survey probes a stellar mass range M*>~10^11.5^ M_{sun}_ and diverse galaxy environments that have not been systematically studied to date. Our wide-field IFS data cover about two effective radii of individual galaxies, and for a subset of them, we are acquiring additional IFS observations on sub-arcsecond scales with adaptive optics. We are also acquiring deep K-band imaging to trace the extended halos of the galaxies and measure accurate total magnitudes. Dynamical orbit modeling of the combined data will allow us to simultaneously determine the stellar, black hole, and dark matter halo masses. The primary goals of the project are to constrain the black hole scaling relations at high masses, investigate systematically the stellar initial mass function and dark matter distribution in massive galaxies, and probe the late-time assembly of ellipticals through stellar population and kinematical gradients. In this paper, we describe the MASSIVE sample selection, discuss the distinct demographics and structural and environmental properties of the selected galaxies, and provide an overview of our basic observational program, science goals and early survey results.
We present the first systematic investigation of the existence, spatial distribution, and kinematics of warm ionized gas as traced by the [OII]3727{AA} emission line in 74 of the most massive galaxies in the local universe. All of our galaxies have deep integral-field spectroscopy from the volume- and magnitude-limited MASSIVE survey of early-type galaxies with stellar mass log(M_*_/M_{sun}_)>11.5 (M_K_<-25.3mag) and distance D<108Mpc. Of the 74 galaxies in our sample, we detect warm ionized gas in 28, which yields a global detection fraction of 38+/-6% down to a typical [OII] equivalent width limit of 2{AA}. MASSIVE fast rotators are more likely to have gas than MASSIVE slow rotators with detection fractions of 80+/-10% and 28+/-6%, respectively. The spatial extents span a wide range of radii (0.6-18.2kpc; 0.1-4R_e_), and the gas morphologies are diverse, with 17/28~61+/-9% being centrally concentrated, 8/28~29+/-9% exhibiting clear rotation out to several kiloparsecs, and 3/28~11+/-6% being extended but patchy. Three out of four fast rotators show kinematic alignment between the stars and gas, whereas the two slow rotators with robust kinematic measurements available exhibit kinematic misalignment. Our inferred warm ionized gas masses are roughly ~10^5^M_{sun}_. The emission line ratios and radial equivalent width profiles are generally consistent with excitation of the gas by the old underlying stellar population. We explore different gas origin scenarios for MASSIVE galaxies and find that a variety of physical processes are likely at play, including internal gas recycling, cooling out of the hot gaseous halo, and gas acquired via mergers.
We present the results of the 2MASS Redshift Survey (2MRS), a ten-year project to map the full three-dimensional distribution of galaxies in the nearby universe. The Two Micron All Sky Survey (2MASS) was completed in 2003 and its final data products, including an extended source catalog (XSC), are available online. The 2MASS XSC contains nearly a million galaxies with Ks<=13.5mag and is essentially complete and mostly unaffected by interstellar extinction and stellar confusion down to a galactic latitude of |b|=5{deg} for bright galaxies. Near-infrared wavelengths are sensitive to the old stellar populations that dominate galaxy masses, making 2MASS an excellent starting point to study the distribution of matter in the nearby universe. We selected a sample of 44599 2MASS galaxies with Ks<=11.75mag and |b|>=5{deg} (>=8{deg} toward the Galactic bulge) as the input catalog for our survey. We obtained spectroscopic observations for 11000 galaxies and used previously obtained velocities for the remainder of the sample to generate a redshift catalog that is 97.6% complete to well-defined limits and covers 91% of the sky. This provides an unprecedented census of galaxy (baryonic mass) concentrations within 300Mpc. Earlier versions of our survey have been used in a number of publications that have studied the bulk motion of the Local Group, mapped the density and peculiar velocity fields out to 50h^-1^Mpc, detected galaxy groups, and estimated the values of several cosmological parameters. Additionally, we present morphological types for a nearly complete sub-sample of 20860 galaxies with Ks<=11.25mag and |b|>=10{deg}.
We create a baseline of the black hole (BH) mass (M_BH_)-stellar-velocity dispersion ({sigma}) relation for active galaxies, using a sample of 66 local (0.02<z<0.09) Seyfert-1 galaxies, selected from the Sloan Digital Sky Survey (SDSS). Analysis of SDSS images yields AGN luminosities free of host-galaxy contamination, and morphological classification. 51/66 galaxies have spiral morphology. Out of these, 28 bulges have Sersic index n<2 and are considered candidate pseudo-bulges, with eight being definite pseudo-bulges based on multiple classification criteria met. Only 4/66 galaxies show signs of interaction/merging. High signal-to-noise ratio Keck spectra provide the width of the broad H{beta} emission line free of Fe II emission and stellar absorption. AGN luminosity and H{beta} line widths are used to estimate M_BH_. The Keck-based spatially resolved kinematics is used to determine stellar-velocity dispersion within the spheroid effective radius ({sigma}_spat,reff_). We find that {sigma} can vary on average by up to 40% across definitions commonly used in the literature, emphasizing the importance of using self-consistent definitions in comparisons and evolutionary studies. The M_BH_-{sigma} relation for our Seyfert-1 galaxy sample has the same intercept and scatter as that of reverberation-mapped AGNs as well as that of quiescent galaxies, consistent with the hypothesis that our single epoch M_BH_ estimator and sample selection function do not introduce significant biases. Barred galaxies, merging galaxies, and those hosting pseudo-bulges do not represent outliers in the M_BH_-{sigma} relation. This is in contrast with previous work, although no firm conclusion can be drawn on this matter due to the small sample size and limited resolution of the SDSS images.
Observations of H_2_O masers from circumnuclear disks in active galaxies for the Megamaser Cosmology Project (MCP) allow accurate measurement of the mass of supermassive black holes (BH) in these galaxies. We present the Very Long Baseline Interferometry images and kinematics of water maser emission in six active galaxies: NGC 1194, NGC 2273, NGC 2960 (Mrk 1419), NGC 4388, NGC 6264 and NGC 6323. We use the Keplerian rotation curves of these six megamaser galaxies, plus a seventh previously published, to determine accurate enclosed masses within the central ~0.3pc of these galaxies, smaller than the radius of the sphere of influence of the central mass in all cases.
Peculiar velocities arise from gravitational instability, and thus are linked to the surrounding distribution of matter. In order to understand the motion of the Local Group with respect to the cosmic microwave background, a deep all-sky map of the galaxy distribution is required. Here we present a new redshift compilation of 69160 galaxies, dubbed 2M++, to map large-scale structures of the local Universe over nearly the whole sky, and reaching depths of K<=12.5, or 200h^-1^Mpc. The target catalogue is based on the Two-Micron All-Sky Survey Extended Source Catalog (2MASS-XSC). The primary sources of redshifts are the 2MASS Redshift Survey, the 6dF galaxy redshift survey and the Sloan Digital Sky Survey (Data Release 7). We assess redshift completeness in each region and compute the weights required to correct for redshift incompleteness and apparent magnitude limits, and discuss corrections for incompleteness in the zone of avoidance. We present the density field for this survey, and discuss the importance of large-scale structures such as the Shapley Concentration.
