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.
Sternberg Astronomical Institute Virtual Observatory Project
Description:
The Two Micron All Sky Survey (2MASS) project is designed to close the
gap between our current technical capability and our knowledge of the
near-infrared sky. In addition to providing a context for the
interpretation of results obtained at infrared and other wavelengths,
2MASS will provide direct answers to immediate questions on the
large-scale structure of the Milky Way and the Local Universe.
To achieve these goals, 2MASS is uniformly scanning the entire sky in
three near-infrared bands to detect and characterize point sources
brighter than about 1 mJy in each band, with signal-to-noise ratio
(SNR) greater than 10, using a pixel size of 2.0". This will achieve
an 80,000-fold improvement in sensitivity relative to earlier surveys.
2MASS uses two new, highly-automated 1.3-m telescopes, one at Mt.
Hopkins, AZ, and one at CTIO, Chile. Each telescope is equipped with a
three-channel camera, each channel consisting of a 256x256 array of
HgCdTe detectors, capable of observing the sky simultaneously at J
(1.25 {mu}m), H (1.65 {mu}m), and Ks (2.17 {mu}m), to a 3{sigma}
limiting sensitivity of 17.1, 16.4 and 15.3mag in the three bands.
The 2MASS arrays image the sky while the telescopes scan smoothly in
declination at a rate of ~1' per second. The 2MASS data "tiles" are 6
deg. long in the declination direction and one camera frame (8.5')
wide. The camera field-of-view shifts by ~1/6 of a frame in
declination from frame-to-frame. The camera images each point on the
sky six times for a total integration time of 7.8 s, with sub-pixel
"dithering", which improves the ultimate spatial resolution of the
final Atlas Images.
The University of Massachusetts (UMass) is responsible for the overall
management of the project, and for developing the infrared cameras and
on-site computing systems at both facilities. The Infrared Processing
and Analysis Center (IPAC) is responsible for all data processing
through the Production Pipeline, and construction and distribution of
the data products. The 2MASS project involves the participation of
members of the Science Team from several different institutions. The
2MASS project is funding by the National Aeronautics and Space
Administration (NASA) and the National Science Foundation (NSF).
Acknowledging 2MASS in publications:
Please include the following in any published material that makes use
of the 2MASS data products:
"This publication makes use of data products from the Two Micron All
Sky Survey, which is a joint project of the University of Massachusetts
and the Infrared Processing and Analysis Center/California Institute of
Technology, funded by the National Aeronautics and Space Administration
and the National Science Foundation."
Sternberg Astronomical Institute Virtual Observatory Project
Description:
The Two Micron All Sky Survey (2MASS) project is designed to close the
gap between our current technical capability and our knowledge of the
near-infrared sky. In addition to providing a context for the
interpretation of results obtained at infrared and other wavelengths,
2MASS will provide direct answers to immediate questions on the
large-scale structure of the Milky Way and the Local Universe.
To achieve these goals, 2MASS is uniformly scanning the entire sky in
three near-infrared bands to detect and characterize point sources
brighter than about 1 mJy in each band, with signal-to-noise ratio
(SNR) greater than 10, using a pixel size of 2.0". This will achieve
an 80,000-fold improvement in sensitivity relative to earlier surveys.
2MASS uses two new, highly-automated 1.3-m telescopes, one at Mt.
Hopkins, AZ, and one at CTIO, Chile. Each telescope is equipped with a
three-channel camera, each channel consisting of a 256x256 array of
HgCdTe detectors, capable of observing the sky simultaneously at J
(1.25 {mu}m), H (1.65 {mu}m), and Ks (2.17 {mu}m), to a 3{sigma}
limiting sensitivity of 17.1, 16.4 and 15.3mag in the three bands.
The 2MASS arrays image the sky while the telescopes scan smoothly in
declination at a rate of ~1' per second. The 2MASS data "tiles" are 6
deg. long in the declination direction and one camera frame (8.5')
wide. The camera field-of-view shifts by ~1/6 of a frame in
declination from frame-to-frame. The camera images each point on the
sky six times for a total integration time of 7.8 s, with sub-pixel
"dithering", which improves the ultimate spatial resolution of the
final Atlas Images.
The University of Massachusetts (UMass) is responsible for the overall
management of the project, and for developing the infrared cameras and
on-site computing systems at both facilities. The Infrared Processing
and Analysis Center (IPAC) is responsible for all data processing
through the Production Pipeline, and construction and distribution of
the data products. The 2MASS project involves the participation of
members of the Science Team from several different institutions. The
2MASS project is funding by the National Aeronautics and Space
Administration (NASA) and the National Science Foundation (NSF).
Acknowledging 2MASS in publications:
Please include the following in any published material that makes use
of the 2MASS data products:
"This publication makes use of data products from the Two Micron All
Sky Survey, which is a joint project of the University of Massachusetts
and the Infrared Processing and Analysis Center/California Institute of
Technology, funded by the National Aeronautics and Space Administration
and the National Science Foundation."
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 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}.
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.
We present a homogeneous 2MASS bright galaxy catalogue at low Galactic latitudes (|b|<=10.0{deg}, called Zone of Avoidance) which is complete to a Galactic extinction-corrected magnitude of KS^o^<=11.25m. It also includes galaxies in regions of high foreground extinctions (E(B-V)>0.95mag) situated at higher latitudes. This catalogue forms the basis of studies of large-scale structures, flow fields and extinction across the ZoA and complements the ongoing 2MASS Redshift and Tully-Fisher surveys. It comprises 3763 galaxies, 70% of which have at least one radial velocity measurement in the literature. The catalogue is complete up to star density levels of logN*/deg^2^<4.5 and at least for A(K)<0.6mag and likely as high as A(K)=20mag. Thus the ZoA in terms of bright NIR galaxies covers only 2.5-4% of the whole sky. We use a diameter-dependent extinction correction to compare our sample with an unobscured, high-latitude sample. While the correction to the Ks -band magnitude is sufficient, the corrected diameters are too small by about 4" on average. The omission of applying such a diameter-dependent extinction correction may lead to a biased flow field even at intermediate extinction values as found in the 2MRS survey. A slight dependence of galaxy colour with stellar density indicates that unsubtracted foreground stars make galaxies appear bluer. Furthermore, far-infrared sources in the DIRBE/IRAS extinction maps that were not removed at low latitudes affect the foreground extinction corrections of three galaxies and may weakly affect a further estimated ~20% of our galaxies.
Hyperluminous infrared galaxies (HLIRGs) are shown to have been more abundant in early epochs. The small samples used in earlier studies are not sufficient to draw robust statistical conclusions regarding the physical properties and the power sources of these extreme infrared (IR) bright galaxies. We make use of multi-wavelength data of a large hyper luminous galaxy sample to derive the main physical properties, such as stellar mass, star formation rate (SFR), volume density, and the contribution to the cosmic stellar mass density and the cosmic SFR density. We also study the black hole (BH) growth rate and its relationship with the SFR of the host galaxy. We selected 526 HLIRGs in three deep fields (Bootes, Lockman-Hole, and ELAIS-N1) and adopted two spectral energy distribution (SED) fitting codes: CIGALE, which assumes energy balance, and CYGNUS, which is based on radiative transfer models and does not adopt an energy balance principle. We used two different active galactic nucleus (AGN) models in CIGALE and three AGN models in CYGNUS to compare results that were estimated using different SED fitting codes and a range of AGN models. The stellar mass, total IR luminosity, and AGN luminosity agree well among different models, with a typical median offset of 0.1dex. The SFR estimates show the largest dispersions (up to 0.5dex). This dispersion has an impact on the subsequent analysis, which may suggest that the previous contradictory results could partly have been due to the different choices in methods. HLIRGs are ultra-massive galaxies, with 99% of them having stellar masses larger than 10^11^M_{sun}_. Our results reveal a higher space density of ultra-massive galaxies than what was found by previous surveys or predicted via simulations. We find that HLIRGs contribute more to the cosmic SFR density as redshift increases. In terms of BH growth, the two SED fitting methods provide different results. We can see a clear trend in whereby SFR decreases as AGN luminosity increases when using CYGNUS estimates. This may possibly imply quenching by AGN in this case, whereas this trend is much weaker when using CIGALE estimates. This difference is also influenced by the dispersion between SFR estimates obtained by the two codes.
Sternberg Astronomical Institute Virtual Observatory Project
Description:
The U.S. Naval Observatory (USNO) announces the release of the first
version of the Naval Observatory Merged Astrometric Dataset
(NOMAD). The almost 100 GB dataset contains astrometric and
photometric data for about 1.1 billion stars derived from the
Hipparcos, Tycho-2, UCAC2, Yellow-Blue 6, and USNO-B catalogs for
astrometry and optical photometry, supplemented by 2MASS near-infrared
photometry. For each unique star the "best" astrometric and
photometric data are chosen from the source catalogs and merged into a
single dataset. A sequence of priorities is followed and NOMAD
contains flags to identify the source catalogs and gives
cross-reference identifications.
This first release of NOMAD is not a compiled catalog; that is, if a
star is identified in more than 1 of the above mentioned catalogs,
only 1 catalog entry is chosen. Thus the local and global systematic
errors of the various source catalogs will be present in this version
of NOMAD. All source catalogs astrometric data are on the
International Celestial Reference System within the limitations of the
source catalogs.
Catalogs used:
Hipparcos Catalogue: Positions, proper motions and errors are used;
however, no parallaxes are included in NOMAD.
Tycho-2: is a compiled catalog with proper motions derived from the
combination of Hipparcos satellite measures (mainly its star tracker
data) and over 100 ground-based astrometric catalogs which provided
the early epoch data. Most of the Tycho B and V magnitudes (which
includes Hipparcos stars) went into NOMAD as well.
UCAC2: is also a compiled catalog, including all catalogs used for
Tycho-2 (thus also including Tycho and Hipparcos astrometric data),
plus the recent epoch ground-based observations of the UCAC project.
However, only 86\% of the sky are covered by UCAC2 (the north
celestial pole area is missing). For stars not in USNO-B, the UCAC2
magnitude has been used as "R" photometry value, although the UCAC2
bandpass is between V and R.
YB6: (Yellow-Blue catalog version 6) is unpublished data obtained from
complete scans of the NPM and SPM plates performed on the PMM at USNO,
Flagstaff Station. The limiting magnitude is about 18 and YB6 is the
major source of faint B and V magnitudes in NOMAD.
2MASS: the near IR photometry without errors or flags has been copied
into NOMAD. For those stars without optical counterparts, the 2MASS
astrometric information was used (no proper motions).
USNO-B: provides positions and proper motions for most faint stars in
NOMAD. Most R photometry in NOMAD comes from this catalog.
For more details, see the catalog introductions for each individual
catalog used in NOMAD.
NOMAD is not a compiled catalog, no average values are taken if a star
appears in more than 1 source catalog. Each astrometric and
photometric entry in NOMAD is taken from a specific source catalog.
The priority order is as follows:
astrometry brighter than 8 mag:
Hipparcos
Tycho-2
UCAC2
astrometry of fainter stars:
Hipparcos
UCAC2
Tycho-2
USNO-B
YB6
2MASS
photometry: optical
Tycho-2 (incl. Hipparcos stars)
YB6
USNO-B
UCAC2
photometry: near IR
2MASS
![To the extent possible under law, the publisher has waived all copyright and related or neighboring rights to the catalogue of astrometric microlensing events. For details, see the `Creative Commons CC0 1.0 Public Domain dedication <http://creativecommons.org/publicdomain/zero/1.0/>`_. Of course, you should still give proper credit when using this data as required by good scientific practice. .. image:: /static/img/cc0.png :alt: [CC0]](/registry-search/?f%5Brights_facet%5D%5B%5D=To+the+extent+possible+under+law%2C+the+publisher+has+waived+all+copyright+and+related+or+neighboring+rights+to+the+catalogue+of+astrometric+++microlensing+events.++For+details%2C+see+the+%60Creative+Commons+CC0+1.0+Public+Domain+dedication+%3Chttp%3A%2F%2Fcreativecommons.org%2Fpublicdomain%2Fzero%2F1.0%2F%3E%60_.++Of+course%2C+you+should+still+give+proper+credit+when+using+this+data+as+required+by+good+scientific+practice.%0A%0A..+image%3A%3A+%2Fstatic%2Fimg%2Fcc0.png%0A+++%3Aalt%3A+%5BCC0%5D%0A%0A&f%5Bsubject_facet_lc%5D%5B%5D=catalogs){kind=link}
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