- ID:
- ivo://CDS.VizieR/J/ApJ/798/95
- Title:
- HE1104-1805 BVRIJ light curves
- Short Name:
- J/ApJ/798/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The gravitationally lensed quasar HE 1104-1805 has been observed at a variety of wavelengths ranging from the mid-infrared to X-ray for nearly 20yr. We combine flux ratios from the literature, including recent Chandra data, with new observations from the SMARTS telescope and Hubble Space Telescope, and use them to investigate the spatial structure of the central regions using a Bayesian Monte Carlo analysis of the microlensing variability. The wide wavelength coverage allows us to constrain not only the accretion disk half-light radius r_1/2_, but the power-law slope {xi} of the size-wavelength relation r_1/2_{prop.to}{lambda}^{xi}^. With a logarithmic prior on the source size, the (observed-frame) R-band half-light radius log (r_1/2_/cm) is 16.0_-0.4_^+0.3^, and the slope {xi} is 1.0_-0.56_^+0.30^. We put upper limits on the source size in soft (0.4-1.2 keV) and hard (1.2-8keV) X-ray bands, finding 95% upper limits on log (r_1/2_/cm) of 15.33 in both bands. A linear prior yields somewhat larger sizes, particularly in the X-ray bands. For comparison, the gravitational radius, using a black hole mass estimated using the H{beta} line, is log(r_g_/cm)=13.94. We find that the accretion disk is probably close to face-on, with cos(i)=1.0 being four times more likely than cos(i)=0.5. We also find probability distributions for the mean mass of the stars in the foreground lensing galaxy, the direction of the transverse peculiar velocity of the lens, and the position angle of the projected accretion disk's major axis (if not face-on).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/838/25
- Title:
- Hectochelle spectroscopy for 776 Kepler stars
- Short Name:
- J/ApJ/838/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The occurrence rate of hot Jupiters from the Kepler transit survey is roughly half that of radial velocity surveys targeting solar neighborhood stars. One hypothesis to explain this difference is that the two surveys target stars with different stellar metallicity distributions. To test this hypothesis, we measure the metallicity distribution of the Kepler targets using the Hectochelle multi-fiber, high-resolution spectrograph. Limiting our spectroscopic analysis to 610 dwarf stars in our sample with logg>3.5, we measure a metallicity distribution characterized by a mean of [M/H]_mean_=-0.045+/-0.009, in agreement with previous studies of the Kepler field target stars. In comparison, the metallicity distribution of the California Planet Search radial velocity sample has a mean of [M/H]_CPS,mean_=-0.005+/-0.006, and the samples come from different parent populations according to a Kolmogorov-Smirnov test. We refit the exponential relation between the fraction of stars hosting a close-in giant planet and the host star metallicity using a sample of dwarf stars from the California Planet Search with updated metallicities. The best-fit relation tells us that the difference in metallicity between the two samples is insufficient to explain the discrepant hot Jupiter occurrence rates; the metallicity difference would need to be ~0.2-0.3dex for perfect agreement. We also show that (sub)giant contamination in the Kepler sample cannot reconcile the two occurrence calculations. We conclude that other factors, such as binary contamination and imperfect stellar properties, must also be at play.
- ID:
- ivo://CDS.VizieR/J/ApJ/660/146
- Title:
- HE 1104-1805 differential light curves
- Short Name:
- J/ApJ/660/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mid-IR flux ratios FA/FB=2.84+/-0.06 of the two images of the gravitationally lensed quasar HE 1104-1805 show no wavelength dependence to within 3% across 3.6-8.0um, show no time dependence over 6 months, and agree with the broad emission-line flux ratios. This indicates that the mid-IR emission likely comes from scales large enough to be little affected by microlensing and that there is little differential extinction between the images. We measure a revised time delay between these two images of 152.2^+2.8^_-3.0_ (1sigma) days from R- and V-band data covering the years 1997-2006. This time delay indicates that the lens has an approximately flat rotation curve over scales of 1-2Re. We also observed uncorrelated variations of ~0.05mag/yr, which we attribute to microlensing of the optical emission from the accretion disk. The optical colors have also changed significantly in the sense that image A is now redder than image B, rather than bluer, as it was in 1993.
- ID:
- ivo://CDS.VizieR/J/AJ/159/278
- Title:
- He-filter observations of WASP-69b & WASP-52b
- Short Name:
- J/AJ/159/278
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared observations of metastable 23S helium absorption with ground- and space-based spectroscopy are rapidly maturing, as this species is a unique probe of exoplanet atmospheres. Specifically, the transit depth in the triplet feature (with vacuum wavelengths near 1083.3nm) can be used to constrain the temperature and mass-loss rate of an exoplanet's upper atmosphere. Here, we present a new photometric technique to measure metastable 23S helium absorption using an ultranarrowband filter (FWHM 0.635nm) coupled to a beam-shaping diffuser installed in the Wide-field Infrared Camera on the 200inch Hale Telescope at Palomar Observatory. We use telluric OH lines and a helium arc lamp to characterize refractive effects through the filter and to confirm our understanding of the filter transmission profile. We benchmark our new technique by observing a transit of WASP-69b and detect an excess absorption of 0.498%{+/-}0.045% (11.1{sigma}), consistent with previous measurements after considering our bandpass. We then use this method to study the inflated gas giant WASP-52b and place a 95th percentile upper limit on excess absorption in our helium bandpass of 0.47%. Using an atmospheric escape model, we constrain the mass-loss rate for WASP-69b to be 5.25_-0.46_^+0.65^x10^-4^M_J_/Gyr (3.32_-0.56_^+0.67^x10^-3^M_J_/Gyr) at 7000K (12000K). Additionally, we set an upper limit on the mass-loss rate of WASP-52b at these temperatures of 2.1x10^-4^M_J_/Gyr (2.1x10^-3^M_J_/Gyr). These results show that ultranarrowband photometry can reliably quantify absorption in the metastable helium feature.
- ID:
- ivo://CDS.VizieR/J/ApJ/798/58
- Title:
- HELGA VI. Giant molecular cloud associations in M31
- Short Name:
- J/ApJ/798/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present a catalog of giant molecular clouds (GMCs) in the Andromeda (M31) galaxy extracted from the Herschel Exploitation of Local Galaxy Andromeda (HELGA) data set. GMCs are identified from the Herschel maps using a hierarchical source extraction algorithm. We present the results of this new catalog and characterize the spatial distribution and spectral energy properties of its clouds based on the radial dust/gas properties found by Smith et al. (Paper II, 2012ApJ...756...40S). A total of 326 GMCs in the mass range 10^4^-10^7^M_{sun}_ are identified; their cumulative mass distribution is found to be proportional to M^-2.34^, in agreement with earlier studies. The GMCs appear to follow the same correlation of cloud mass to L_CO_ observed in the Milky Way. However, comparison between this catalog and interferometry studies also shows that the GMCs are substructured below the Herschel resolution limit, suggesting that we are observing associations of GMCs. Following Gordon et al. (2006ApJ...638L..87G), we study the spatial structure of M31 by splitting the observed structure into a set of spiral arms and offset rings. We fit radii of 10.3 and 15.5kpc to the two most prominent rings. We then fit a logarithmic spiral with a pitch angle of 8.9{deg} to the GMCs not associated with either ring. Last, we comment on the effects of deprojection on our results and investigate the effect different models for M31's inclination will have on the projection of an unperturbed spiral arm system.
- ID:
- ivo://CDS.VizieR/J/ApJ/885/74
- Title:
- 1340 Helium rich white dwarfs in the Gaia era
- Short Name:
- J/ApJ/885/74
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- We present an analysis of 1023 DBZ/DZ(A) and 319 DQ white dwarf stars taken from the Montreal White Dwarf Database. This represents a significant increase over the previous comprehensive studies on these types of objects. We use new trigonometric parallax measurements from the Gaia second data release, together with photometry from the Sloan Digital Sky Survey, Pan-STARRS, Gaia, or BVRI from the literature, which allow the determination of the mass for the majority of the objects in our sample. We use the photometric and spectroscopic techniques with our recently improved model atmospheres code, which include high-density effects, to accurately determine the effective temperature, surface gravity, and heavy-element abundances for each object. We study the abundance of hydrogen in DBZ/DZ white dwarfs and the properties of the accreted planetesimals. We explore the nature of the second sequence of DQ stars using proper motions from Gaia and highlight evidence of crystallization in massive DQ stars. We also present mass distributions for both spectral types. Finally, we discuss the implications of our findings in the context of the spectral evolution of white dwarfs and provide the atmospheric parameters for each star.
- ID:
- ivo://CDS.VizieR/J/A+A/580/A19
- Title:
- Hen 2-155 and Hen 2-161 photometry and spectroscopy
- Short Name:
- J/A+A/580/A19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of Hen 2-155 and Hen 2-161, two planetary nebulae which bear striking morphological similarities to other planetary nebulae known to host close-binary central stars. Both central stars are revealed to be photometric variables while spectroscopic observations confirm that Hen 2-155 is host to a double-eclipsing, post-common-envelope system with an orbital period of 3h 33m making it one of the shortest period binary central stars known. The observations of Hen 2-161 are found to be consistent with a post-common-envelope binary of period ~1-day.
- ID:
- ivo://CDS.VizieR/J/AJ/118/1043
- Title:
- Herbig Ae/Be stars catalog
- Short Name:
- J/AJ/118/1043
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVR photometric monitoring of Herbig Ae/Be stars and some related objects has been carried out at Maidanak Observatory in Uzbekistan since 1983. More than 71,000 observations of about 230 stars have been obtained and are made available for anonymous ftp. Virtually all Herbig Ae/Be stars observed are irregular variables (called "UXors" after UX Ori), but there is a wide range of amplitudes from barely detectable to more than 4mag in V. Our data confirm the results of previous studies, which indicate that large-amplitude variability is confined to stars with spectral types later than B8. The distribution of variability ranges is quite similar to what is seen in classical T Tauri stars.
- ID:
- ivo://CDS.VizieR/J/AJ/115/6
- Title:
- Hercules supercluster kinematics
- Short Name:
- J/AJ/115/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hercules supercluster consists of the Abell clusters A2147, A2151, and A2152. Previous studies of the kinematics have been confounded by the difficulty of correctly assigning galaxies to the individual clusters, which are not well separated. Our study has a total of 468 available velocities for galaxies in the region, 175 of them new. There are 414 galaxies in the supercluster, about 3 times the number used in the previous supercluster study. We verify the existence of the three individual clusters and compute their individual dynamical parameters. We investigate several techniques for assigning galaxy membership to clusters in this crowded field. We use the Kaye's mixture model (Ashman, Bird, & Zepf, 1994AJ....108.2348A) algorithm to separate the galaxies into clusters; we find that A2152 has a higher mean velocity than previous studies have reported. A2147 and A2152 also have lower velocity dispersions: 821^+68^_-55_ and 715^+81^_-61_km/s, respectively. The assignment of galaxies to either A2152 or A2147 requires velocity and position information. We study the kinematics of the supercluster using the two-body formalism of Beers, Geller, & Huchra (1982ApJ...257...23B) and conclude that A2147 and A2151 are probably bound to each other and that the supercluster as a whole may also be bound. The mass of the supercluster, if bound, is (7.6+/-2.0)x10^15^h^-1^M_{sun}_; with the supercluster luminosity, (1.4+/-0.2)x10^13^h^-2^L_{sun}_, this yields {OMEGA}=0.34+/-0.1.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/1989
- Title:
- HerMES Large Mode Survey catalogue
- Short Name:
- J/MNRAS/462/1989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Selecting sources with rising flux densities towards longer wavelengths from Herschel/Spectral and Photometric Imaging Receiver (SPIRE) maps is an efficient way to produce a catalogue rich in high-redshift (z>4) dusty star-forming galaxies. The effectiveness of this approach has already been confirmed by spectroscopic follow-up observations, but the previously available catalogues made this way are limited by small survey areas. Here we apply a map-based search method to 274deg^2^ of the Herschel Multi-tiered Extragalactic Survey (HerMES) Large Mode Survey and create a catalogue of 477 objects with SPIRE flux densities S_500_>S_350_>S_250_ and a 5{sigma} cut-off S_500_>52mJy. From this catalogue we determine that the total number of these 'red' sources is at least an order of magnitude higher than predicted by galaxy evolution models. These results are in agreement with previous findings in smaller HerMES fields; however, due to our significantly larger sample size we are also able to investigate the shape of the red source counts for the first time. We have obtained spectroscopic redshift measurements for two of our sources using the Atacama Large Millimeter/submillimeter Array. The redshifts z=5.1 and 3.8 confirm that with our selection method we can indeed find high-redshift dusty star-forming galaxies.
