- ID:
- ivo://CDS.VizieR/J/ApJ/736/31
- Title:
- HETDEX pilot survey. II. 1.9<z<3.8 LAEs
- Short Name:
- J/ApJ/736/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the escape of Ly{alpha} photons from Ly{alpha} emitting galaxies (LAEs) and the overall galaxy population using a sample of 99 LAEs at 1.9<z<3.8 detected through integral-field spectroscopy of blank fields by The Hobby Eberly Telescope Dark Energy Experiment Pilot Survey. For 89 LAEs with broadband counterparts we measure ultraviolet (UV) luminosities and UV slopes, and estimate E(B-V) under the assumption of a constant intrinsic UV slope for LAEs. These quantities are used to estimate dust-corrected star formation rates (SFRs). Comparison between the observed Ly{alpha} luminosity and that predicted by the dust-corrected SFR yields the Ly{alpha} escape fraction. We also measure the Ly{alpha} luminosity function and luminosity density ({rho}_Ly{alpha}_) at 2<z<4. Using this and other measurements from the literature at 0.3<z<7.7 we trace the redshift evolution of {rho}_Ly{alpha}_. We compare it to the expectations from the star formation history of the universe and characterize the evolution of the Ly{alpha} escape fraction of galaxies.
Number of results to display per page
Search Results
- ID:
- ivo://nasa.heasarc/hete2gcn
- Title:
- HETE-2 GCN Triggers Catalog
- Short Name:
- HETE2GCN
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- HETE-2 (the High Energy Transient Explorer) is an international mission designed to help unravel the mystery of Gamma-Ray Bursts (GRBs). The primary goal of HETE-2 is to determine the origin and nature of cosmic gamma-ray bursts (GRBs) by simultaneous observation of soft and medium X-rays and gamma-rays to provide precise localization of GRBs and identification of counterparts to these explosions. HETE-2 carries three science instruments: a set of wide-field gamma-ray spectrometers (FREGATE), a wide-field X-ray monitor (WXM, and a set of soft X-ray cameras (SXC) HETE-2 was launched on October 9, 2000, and declared fully operational on February 6, 2001. The contents of this HEASARC database table are based on online tables created by Scott Barthelmy and available at the <a href="http://gcn.gsfc.nasa.gov/">http://gcn.gsfc.nasa.gov/</a> web site. The HEASARC table will be updated on a twice-per-week basis whenever the original tables are updated. This is a service provided by NASA HEASARC .
6133. HETE-2 Timeline
- ID:
- ivo://nasa.heasarc/hete2tl
- Title:
- HETE-2 Timeline
- Short Name:
- HETE2
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The HETE2TL database table records the pointing direction of the HETE-2 boresight camera and the roll angle of the HETE-2 spacecraft at each given time, as determined by the aspect camera/optical sub-system aboard HETE-2. HETE-2 (the High Energy Transient Explorer) is an international mission designed to help unravel the mystery of Gamma-Ray Bursts (GRBs). The primary goal of HETE-2 is to determine the origin and nature of cosmic gamma-ray bursts (GRBs) by simultaneous observation of soft and medium X-rays and gamma-rays to provide precise localization of GRBs and identification of counterparts to these explosions. HETE-2 carries three science instruments: a set of wide-field gamma-ray spectrometers (FREGATE), a wide-field X-ray monitor (WXM, and a set of soft X-ray cameras (SXC) HETE-2 was launched on October 9, 2000, and declared fully operational on February 6, 2001. While this mission was active, this HEASARC database table was updated on a thrice-per-week basis, depending upon updates to the timeline file. The last update that was provided was in August 2006. Some duplicate entries were remove in June 2019. This is a service provided by NASA HEASARC .
6134. HETE Trigger Information
- ID:
- ivo://CDS.VizieR/J/other/GCN/1070.1
- Title:
- HETE Trigger Information
- Short Name:
- J/other/GCN/1070
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- At 15:54:53.123 UT on 23 June, the HETE FREGATE and WXM instruments detected and localized an intense burst from SGR1806-20, a soft gamma-ray repeater. This event, disseminated in near real time as a GCN Alert (HETE BID_1566; see http://gcn.gsfc.nasa.gov/gcn/hete_grbs.html ), is the second burst localized from this source in the past week. (The first burst was reported in GCN Circular #1068). The coordinates (J2000) of the 23 June burst are: RA=272.1460{deg} (18:08:35.02), DE=-20.3658{deg} (-20:21:56) The error circle for this localization is 6 arcmin in radius. SGR1806-20 lies 3.1arcmin from the HETE position. The burst duration in the 8-40keV band was ~200ms, comprised of two peaks each <100ms in duration. A total of 2250 counts were detected during that interval, corresponding to a fluence of ~4x10^-7^ergs/cm^2^. The peak flux was >6x10^-6^erg/cm^2^/s (i.e. >200Crab-flux). Follow-up observations of this transient are encouraged. Additional information on this burst detection (including light curves), as well as for the HETE mission, will be available at: http://space.mit.edu/HETE/
- ID:
- ivo://CDS.VizieR/J/ApJS/218/10
- Title:
- HET Massive Galaxy Survey (HETMGS)
- Short Name:
- J/ApJS/218/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted an optical long-slit spectroscopic survey of 1022 galaxies using the 10m Hobby-Eberly Telescope (HET) at McDonald Observatory. The main goal of the HET Massive Galaxy Survey (HETMGS) is to find nearby galaxies that are suitable for black hole mass measurements. In order to measure accurately the black hole mass, one should kinematically resolve the region where the black hole dominates the gravitational potential. For most galaxies, this region is much less than an arcsecond. Thus, black hole masses are best measured in nearby galaxies with telescopes that obtain high spatial resolution. The HETMGS focuses on those galaxies predicted to have the largest sphere-of-influence, based on published stellar velocity dispersions or the galaxy fundamental plane. To ensure coverage over galaxy types, the survey targets those galaxies across a face-on projection of the fundamental plane. We present the sample selection and resulting data products from the long-slit observations, including central stellar kinematics and emission line ratios. The full data set, including spectra and resolved kinematics, is available online. Additionally, we show that the current crop of black hole masses are highly biased toward dense galaxies and that especially large disks and low dispersion galaxies are under-represented. This survey provides the necessary groundwork for future systematic black hole mass measurement campaigns.
- ID:
- ivo://CDS.VizieR/J/A+A/573/A129
- Title:
- HeViCS. SPIRE point-source catalogs
- Short Name:
- J/A+A/573/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present three independent catalogs of point-sources extracted from SPIRE images at 250, 350, and 500 micron, acquired with the Herschel Space Observatory as a part of the Herschel Virgo Cluster Survey (HeViCS). The catalogs have been cross-correlated to consistently extract the photometry at SPIRE wavelengths for each object. Sources have been detected using an iterative loop. The source positions are determined by estimating the likelihood to be a real source for each peak on the maps, according to the criterion defined in the sourceExtractorSussextractor task. The flux densities are estimated using the sourceExtractorTimeline, a timeline-based point source fitter that also determines the fitting procedure with the width of the Gaussian that best reproduces the source considered. Afterwards, each source is subtracted from the maps, removing a Gaussian function in every position with the full width half maximum equal to that estimated in sourceExtractorTimeline.
- ID:
- ivo://CDS.VizieR/J/A+A/574/A126
- Title:
- HeViCS. XVIII. Star-forming dwarf galaxies
- Short Name:
- J/A+A/574/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the far-infrared (FIR) and submillimetre (submm) properties of a sample of star-forming dwarf galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of a total 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than m_B_=18mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by {beta}=1.5, with a median dust temperature T_d_=22.4K. Assuming {beta}=1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500{mu}m in excess of the modified black-body model. The fraction of galaxies with a submillimetre excess decreases for lower values of {beta}, while a similarly high fraction (54%) is found if a {beta}-free SED modelling is applied. The excess is inversely correlated with SFR and stellar masses. To study the variations in the global properties of our sample that come from environmental effects, we compare the Virgo dwarfs to other Herschel surveys, such as the Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH), the Dwarf Galaxy Survey (DGS), and the HeViCS Bright Galaxy Catalogue (BGC). We explore the relations between stellar mass and HI fraction, specific star formation rate, dust fraction, gas-to-dust ratio over a wide range of stellar masses (from 10^7^ to 10^11^M_{sun}_) for both dwarfs and spirals. Highly HI-deficient Virgo dwarf galaxies are mostly characterised by quenched star formation activity and lower dust fractions giving hints for dust stripping in cluster dwarfs. However, to explain the large dust-to-gas mass ratios observed in these systems, we find that the fraction of dust removed has to be less than that of the HI component. The cluster environment seems to mostly affect the gas component and star formation activity of the dwarfs. Since the Virgo star-forming dwarfs are likely to be crossing the cluster for the first time, a longer timescale might be necessary to strip the more centrally concentrated dust distribution.
- ID:
- ivo://nasa.heasarc/exgalemobj
- Title:
- Hewitt&Burbidge(1991)CatalogofExtragalacticEmission-LineObjects
- Short Name:
- H&B91
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This is the Hewitt & Burbidge (1991) Optical Catalog of Extragalactic Emission-Line Objects Similar to Quasi-Stellar Objects. It contains a total of 935 galaxies which have optical properties similar to QSOs. Most of the objects appear to be nonstellar. The majority, more than 700, have redshifts z that are <= 0.2, and most have been classified as Seyfert galaxies, N systems, or radio galaxies. The redshift distribution peaks at z ~ 0.025, but there are about 200 powerful radio galaxies in the extended tail of the distribution which have z > 0.2. There is a separate and distinct peak in the redshift distribution at z = 0.06. Notice that this catalog does not include star-like objects with emission-line redshifts >= 0.1 (these can be found in the HEASARC QSO database which contains the Revised and Updated Catalog of Quasi-Stellar Objects" of Hewitt, A. and Burbidge, G. 1993, ApJS, Vol. 87, pp. 451-947). Neither does it contain LINERs (sometimes called Seyfert 3 galaxies) or starburst galaxies. This database was created by the HEASARC in February 2001 based on CDS/ADC Catalog VII/178 (table1.dat). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/qso
- Title:
- Hewitt&Burbidge(1993)QSOCatalog
- Short Name:
- HB
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This is (a somewhat condensed form of) the Hewitt & Burbidge (1993) Revised and Updated Catalog of Quasi-Stellar Objects, and contains all then-known (to 1992 December 31) quasi-stellar objects (QSOs) with measured emission redshifts and BL Lac objects. The catalog contains 7315 objects, nearly all of which are quasi-stellar objects, and 89 of which are BL Lac objects. It contains extensive information on names, positions, magnitudes, colors, emission-line redshifts, absorption-line systems, etc. The published version of this catalog (Hewitt & Burbidge 1993, ApJS, 87, 451) typically contained multiple rows on information for each object. This database basically has only the information given in the first row for every object, and is based on the CDS/ADC table VII/158 table1_1.dat.gz. This database was created by the HEASARC in February 2001 based on CDS/ADC Catalog VII/158 (table1_1.dat.gz). This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/A+A/426/171
- Title:
- H_2_ flows in rho Ophiuchi A
- Short Name:
- J/A+A/426/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an unbiased search for molecular hydrogen emission in the L1688 cloud within the rho Ophiuchi molecular cloud complex. Our near-infrared survey covers a connected region of extent 35'x35'. We detect several new H_2_ flows but the total number of detected outflows is low and is consistent with the paucity of Class 0 and Class 1 sources in the molecular cloud. From the spatial distribution, their collimation and the individual shapes of the bow shocks, we suggest possible candidates for the outflow sources. Most of the candidate driving sources are deeply embedded in dense cores of the molecular cloud. A very young outflow arises from the newly discovered Class 0 source MMS 126. Two major outflows in the NE-SW direction arise from the YLW 15 and YLW 16 Class I sources. Three additional outflows, which both extend over several arcminutes, arise from the Class I sources YLW 31 and YLW 52. Flow directions are generally NE-SW, perpendicular to the elongation directions of the cloud filaments. The apparent extents of molecular flows are related to either the widths of cloud filaments or to the separation between filaments. The estimated jet power needed to continuously drive and excite the detected portions of the shocked H_2_ outflows lies in the range 0.02-0.2L_{sun}_. Given the critical dependence on the environment, however, the total sizes and powers of the outflows may be considerably larger.