- ID:
- ivo://CDS.VizieR/J/ApJS/220/10
- Title:
- AEGIS-X Deep survey of EGS (AEGIS-XD)
- Short Name:
- J/ApJS/220/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of deep Chandra imaging of the central region of the Extended Groth Strip, the AEGIS-X Deep (AEGIS-XD) survey. When combined with previous Chandra observations of a wider area of the strip, AEGIS-X Wide (AEGIS-XW), these provide data to a nominal exposure depth of 800ks in the three central ACIS-I fields, a region of approximately 0.29deg^2^. This is currently the third deepest X-ray survey in existence; a factor ~2-3 shallower than the Chandra Deep Fields (CDFs), but over an area ~3 times greater than each CDF. We present a catalog of 937 point sources detected in the deep Chandra observations, along with identifications of our X-ray sources from deep ground-based, Spitzer, GALEX, and Hubble Space Telescope imaging. Using a likelihood ratio analysis, we associate multiband counterparts for 929/937 of our X-ray sources, with an estimated 95% reliability, making the identification completeness approximately 94% in a statistical sense. Reliable spectroscopic redshifts for 353 of our X-ray sources are available predominantly from Keck (DEEP2/3) and MMT Hectospec, so the current spectroscopic completeness is ~38%. For the remainder of the X-ray sources, we compute photometric redshifts based on multiband photometry in up to 35 bands from the UV to mid-IR. Particular attention is given to the fact that the vast majority the X-ray sources are active galactic nuclei and require hybrid templates. Our photometric redshifts have mean accuracy of {sigma}=0.04 and an outlier fraction of approximately 5%, reaching {sigma}=0.03 with less than 4% outliers in the area covered by CANDELS.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/273/157
- Title:
- A faint galaxy survey to B = 24.
- Short Name:
- J/MNRAS/273/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the multi-slit LDSS-2 spectrograph on the William Herschel Telescope we have completed a redshift survey in the magnitude range 22.5<B<24 which produced 73 redshifts representing a 73% complete sample uniformly selected from four deep fields at high galactic latitude. The survey extends to z>1 and includes the highest redshift galaxy (z=1.108) yet discovered in a field sample.
- ID:
- ivo://CDS.VizieR/J/AJ/117/446
- Title:
- AFGL 5157 near-IR imaging
- Short Name:
- J/AJ/117/446
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared images of the star-forming region AFGL 5157 in the JHK broadband filters and H_2_v=1-0S(1) narrowband filter. The images reveal a dense cluster of stars and infrared nebulosities associated with previously known infrared sources. Of 54 near-infrared sources detected in the nebula, NGC 1985, 12 exhibit infrared excesses typical of T Tauri stars, Herbig Ae/Be stars, and protostars. The magnitude and color distribution of the cluster of stars in the nebula are found to be different from those outside the nebular region. The K'-magnitude distribution of the cluster is quite flat, while the noncluster is peaked toward the low magnitude. The [H-K'] color of the cluster also displays 0.3 mag redder than that of the noncluster. The infrared nebula displays a bright nucleus with two spirals extended to the north and south. In light of the color properties of the nebula, we propose a shell model for the nebular structure that could be formed by star-forming activity of the central cluster.
- ID:
- ivo://CDS.VizieR/II/212A
- Title:
- A Finding List of Faint UV-Bright Stars
- Short Name:
- II/212A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 195 UV-bright stars have been found on two-color 48-inch Schmidt plates centered on the galactic plane, and on one high-latitude plate. This catalog contains sources with (U-B) in the range U-B=0 to U-B=-1.5.
- ID:
- ivo://CDS.VizieR/II/231
- Title:
- A Finding List of Faint UV-Bright Stars
- Short Name:
- II/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The survey lists the very blue objects found on the plates taken for the Sandage Two-Color Survey of the Galactic Plane obtained using the Palomar 48 inch Oschin Schmidt telescope. The sources range in U-B color from U-B~-0.1 to U-B~-1.0 and in magnitude from m_B_~10 to ~20.
- ID:
- ivo://CDS.VizieR/II/257A
- Title:
- A Finding List of Faint UV-Bright Stars
- Short Name:
- II/257A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The survey lists the very blue objects found on the plates taken for the Sandage Two-Color Survey of the Galactic Plane obtained using the Palomar 48 inch Oschin Schmidt telescope. The sources range in U-B color from U-B~-0.1 to U-B~-1.0 and in magnitude from m_B_~10 to ~20.
- ID:
- ivo://CDS.VizieR/J/AJ/156/241
- Title:
- A first catalog of variable stars measured by ATLAS
- Short Name:
- J/AJ/156/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Asteroid Terrestrial-impact Last Alert System (ATLAS) carries out its primary planetary defense mission by surveying about 13000 deg^2^ at least four times per night. The resulting data set is useful for the discovery of variable stars to a magnitude limit fainter than r~18, with amplitudes down to 0.02 mag for bright objects. Here, we present a Data Release One catalog of variable stars based on analyzing the light curves of 142 million stars that were measured at least 100 times in the first two years of ATLAS operations. Using a Lomb-Scargle periodogram and other variability metrics, we identify 4.7 million candidate variables. Through the Space Telescope Science Institute, we publicly release light curves for all of them, together with a vector of 169 classification features for each star. We do this at the level of unconfirmed candidate variables in order to provide the community with a large set of homogeneously analyzed photometry and to avoid pre-judging which types of objects others may find most interesting. We use machine learning to classify the candidates into 15 different broad categories based on light-curve morphology. About 10% (427000 stars) pass extensive tests designed to screen out spurious variability detections: we label these as "probable" variables. Of these, 214000 receive specific classifications as eclipsing binaries, pulsating, Mira-type, or sinusoidal variables: these are the "classified" variables. New discoveries among the probable variables number 315000, while 141000 of the classified variables are new, including about 10400 pulsating variables, 2060 Mira stars, and 74700 eclipsing binaries.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/862
- Title:
- Afterglow light curve of GRB 090926A
- Short Name:
- J/ApJ/720/862
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VLT/FORS2 spectroscopy and Gamma-ray Optical/Near-Infrared Detector optical/near-IR photometry of the afterglow of the bright Fermi/LAT GRB 090926A. The spectrum shows prominent Lyman-{alpha} absorption with N_HI_=10^21.73+/-0.07^cm^-2^ and a multitude of metal lines at a common redshift of z=2.1062+/-0.0004, which we associate with the redshift of the gamma-ray burst (GRB). The metallicity derived from SII is log(Z/Z_{sun}_)~-1.9, one of the lowest values ever found in a GRB Damped Lyman-{alpha} (DLA) system. This confirms that the spread of metallicity in GRB-DLAs at z~2 is at least two orders of magnitude. We argue that this spread in metallicity does not require a similar range in abundances of the GRB progenitors, since the neutral interstellar medium probed by the DLA is expected to be at a significant distance from the explosion site. The hydrogen column density derived from the Swift/XRT afterglow spectrum (assuming log(Z/Z_{sun}_)~-1.9) is ~100 times higher than the N_HI_ obtained from the Lyman-{alpha} absorptions. This suggests either a large column density of ionized gas or a higher metallicity of the circum-burst medium compared to the gas traced by the DLA. We also discuss the afterglow light curve evolution and energetics. The absence of a clear jet-break like steeping until at least 21 days post-burst suggests a beaming-corrected energy release of E_{gamma}_>3.5x10^52^erg, indicating that GRB 090926A may have been one of the most energetic bursts ever detected.
- ID:
- ivo://CDS.VizieR/J/ApJ/701/824
- Title:
- Afterglows of short and long-duration GRBs
- Short Name:
- J/ApJ/701/824
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparative study of the observed properties of the optical and X-ray afterglows of short- and long-duration {gamma}-ray bursts (GRBs). Using a large sample of 37 short and 421 long GRBs, we find a strong correlation between the afterglow brightness measured after 11hr and the observed fluence of the prompt emission. Both the optical (R band) and X-ray flux densities (F_R_ and F_X_) scale with the {gamma}-ray fluence, F_{gamma}_. For bursts with a known redshift, a tight correlation exists between the afterglow flux densities at 11hr (rest frame) and the total isotropic {gamma}-ray energy, E_{gamma},ISO_: F_R,X_{prop.to}E_{gamma},ISO_^{alpha}^, with {alpha}~1.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/1840
- Title:
- A3266 galaxies at 24um
- Short Name:
- J/ApJ/693/1840
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Multiband Imaging Photometer observations of the cluster A3266. About 100 spectroscopic cluster members have been detected at 24um. The infrared (IR) luminosity function (LF) in A3266 is very similar to that in the Coma cluster down to the detection limit LIR~10^43^erg/s, suggesting a universal form of the bright-end IR LF for local rich clusters with M~10^15^M_{sun}_. The shape of the bright end of the A3266-Coma composite IR LF is not significantly different from that of nearby field galaxies, but the fraction of IR-bright galaxies (star formation rate (SFR)>0.2M_{sun}_/yr) in both clusters increases with cluster-centric radius. The decrease of the blue galaxy fraction toward the high-density cores only accounts for part of the trend; the fraction of red galaxies with moderate SFRs (0.2M_{sun}_/yr<SFR<1M_{sun}/yr) also decreases with increasing galaxy density. These results suggest that for the IR-bright galaxies nearby rich clusters are distinguished from the field by a lower star forming galaxy fraction, but not by a change in L*_IR_.
