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2841. Hydrogen Lyman and Balmer line profiles
ID:
ivo://CDS.VizieR/J/MNRAS/448/2332
Title:
Hydrogen Lyman and Balmer line profiles
Short Name:
J/MNRAS/448/2332
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new calculations of unified line profiles for hydrogen perturbed by collisions with protons. We report on new calculations of the potential energies and dipole moments which allow the evaluation of profiles for the lines of the Lyman series up to Lyman {delta} and the Balmer series up to Balmer 10. Unified calculations only existed for the lines Lyman {alpha} to Lyman {gamma} and Balmer {alpha} including the H_2_^+^ quasi-molecule. These data are available as online material accompanying this paper and should be included in atmosphere models, in place of the Stark effect of protons, since the quasi-molecular contributions cause not only satellites, but large asymmetries that are unaccounted for in models that assume that Stark broadening of electrons and that of protons are equal.
2842. Hypervelocity stars. II.
ID:
ivo://CDS.VizieR/J/ApJ/660/311
Title:
Hypervelocity stars. II.
Short Name:
J/ApJ/660/311
Date:
21 Oct 2021
Publisher:
CDS
Description:
Hypervelocity stars (HVSs) are stars ejected completely out of the Milky Way by three-body interactions with the massive black hole in the Galactic center. We describe 643 new spectroscopic observations from our targeted survey for HVSs. We find a significant (3.5{sigma}) excess of B-type stars with large velocities +275km/s<V_rf_<450km/s and distances d>10kpc that are most plausibly explained as a new class of HVSs: stars ejected from the Galactic center on bound orbits. If a Galactic center ejection origin is correct, the distribution of HVSs on the sky should be anisotropic for a survey complete to a fixed limiting apparent magnitude. The unbound HVSs in our survey have a marginally anisotropic distribution on the sky, consistent with the Galactic center ejection picture.
2843. Hypervelocity stars. III
ID:
ivo://CDS.VizieR/J/ApJ/671/1708
Title:
Hypervelocity stars. III
Short Name:
J/ApJ/671/1708
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of three new unbound hypervelocity stars (HVSs), stars travelling with such extreme velocities that dynamical ejection from a massive black hole (MBH) is their only suggested origin. We also detect a population of possibly bound HVSs.
2844. IAC Stripe 82 Legacy Project: Photometry
ID:
ivo://CDS.VizieR/J/MNRAS/456/1359
Title:
IAC Stripe 82 Legacy Project: Photometry
Short Name:
J/MNRAS/456/1359
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new deep co-adds of data taken within Stripe 82 of the Sloan Digital Sky Survey (SDSS), especially stacked to reach the faintest surface brightness limits of this data set. Stripe 82 covers 275 square degrees within -50{deg}<=RA<=+60{deg} and -1.26{deg}<=DE<=+1.25{deg}. We discuss the steps of our reduction which puts special emphasis on preserving the characteristics of the background (sky + diffuse light) in the input images using a non-aggressive sky subtraction strategy. Our reduction reaches a limit of ~28.5 mag/arcsec^2^ (3{sigma}, 10x10 arcsec^2^) in the r band. The effective surface brightness limit (50 per cent completeness for exponential light distribution) lies at <{mu}e(r)>~25.5mag/arcsec^2^. For point sources, we reach 50 per cent completeness limits (3{sigma} level) of (24.2, 25.2, 24.7, 24.3, 23.0) mag in (u, g, r, i, z). This is between 1.7 and 2.0mag deeper than the single-epoch SDSS releases. The co-adds show point spread functions (PSFs) with median full width at half-maximum values ranging from 1-arcsec in i and z to 1.3-arcsec in the u band. The imaging data are made publicly available at http://www.iac.es/proyecto/stripe82. The release includes deep co-adds and representations of the PSF for each field. Additionally, we provide object catalogues with stars and galaxies confidently separated until g~23mag. The IAC Stripe 82 co-adds offer a rather unique possibility to study the low surface brightness Universe, exemplified by the discovery of stellar streams around NGC 0426 and NGC 0936. We also discuss further science cases like stellar haloes and disc truncations, low surface brightness galaxies, the intracluster light in galaxy clusters and the diffuse emission of Galactic dust known as Galactic Cirrus.
2845. I-band GALFIT analysis of luminous infrared galaxies
ID:
ivo://CDS.VizieR/J/ApJ/768/102
Title:
I-band GALFIT analysis of luminous infrared galaxies
Short Name:
J/ApJ/768/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
A Hubble Space Telescope/Advanced Camera for Surveys study of the structural properties of 85 luminous and ultraluminous (L_IR_>10^11.4^ L_{sun}_) infrared galaxies (LIRGs and ULIRGs) in the Great Observatories All-sky LIRG Survey (GOALS) sample is presented. Two-dimensional GALFIT analysis has been performed on F814W "I-band" images to decompose each galaxy, as appropriate, into bulge, disk, central point-spread function (PSF) and stellar bar components. The fraction of bulge-less disk systems is observed to be higher in LIRGs (35%) than in ULIRGs (20%), with the disk+bulge systems making up the dominant fraction of both LIRGs (55%) and ULIRGs (45%). Further, bulge+disk systems are the dominant late-stage merger galaxy type and are the dominant type for LIRGs and ULIRGs at almost every stage of galaxy-galaxy nuclear separation. The mean I-band host absolute magnitude of the GOALS galaxies is -22.64+/-0.62 mag (1.8_-0.4_^+1.4^ L_1_^*^), and the mean bulge absolute magnitude in GOALS galaxies is about 1.1 mag fainter than the mean host magnitude. Almost all ULIRGs have bulge magnitudes at the high end (-20.6 to -23.5 mag) of the GOALS bulge magnitude range. Mass ratios in the GOALS binary systems are consistent with most of the galaxies being the result of major mergers, and an examination of the residual-to-host intensity ratios in GOALS binary systems suggests that smaller companions suffer more tidal distortion than the larger companions. We find approximately twice as many bars in GOALS disk+bulge systems (32.8%) than in pure-disk mergers (15.9%) but most of the disk+bulge systems that contain bars are disk-dominated with small bulges. The bar-to-host intensity ratio, bar half-light radius, and bar ellipticity in GOALS galaxies are similar to those found in nearby spiral galaxies. The fraction of stellar bars decreases toward later merger stages and smaller nuclear separations, indicating that bars are destroyed as the merger advances. In contrast, the fraction of nuclear PSFs increases toward later merger stages and is highest in late-stage systems with a single nucleus. Thus, light from an active galactic nucleus or compact nuclear star cluster is more visible at I band as ULIRGs enter their latter stages of evolution. Finally, both GOALS elliptical hosts and nearby Sloan Digital Sky Survey (SDSS) ellipticals occupy the same part of the surface brightness versus half-light radius plot (i.e., the "Kormendy Relation") and have similar slopes, consistent with the possibility that the GOALS galaxies belong to the same parent population as the SDSS ellipticals.
2846. I-band LC of the microlensing event KMT-2017-BLG-2820
ID:
ivo://CDS.VizieR/J/AJ/161/126
Title:
I-band LC of the microlensing event KMT-2017-BLG-2820
Short Name:
J/AJ/161/126
Date:
10 Dec 2021
Publisher:
CDS
Description:
We report a new free-floating planet (FFP) candidate, KMT-2017-BLG-2820, with Einstein radius {theta}E~6{mu}as, lens-source relative proper motion {mu}rel~8mas/yr, and Einstein timescale t_E_=6.5hr. It is the third FFP candidate found in an ongoing study of giant-source finite-source point-lens (FSPL) events in the KMTNet database and the sixth FSPL FFP candidate overall. We find no significant evidence for a host. Based on their timescale distributions and detection rates, we argue that five of these six FSPL FFP candidates are drawn from the same population as the six point-source point-lens (PSPL) FFP candidates found by Mroz et al. in the OGLE-IV database. The {theta}E distribution of the FSPL FFPs implies that they are either sub- Jovian planets in the bulge or super-Earths in the disk. However, the apparent "Einstein desert" (10<~{theta}E/{mu}as<~30) would argue for the latter. Whether each of the 12 (six FSPL and six PSPL) FFP candidates is truly an FFP or simply a very wide-separation planet can be determined at first adaptive optics (AO) light on 30m telescopes, and earlier for some. If the latter, a second epoch of AO observations could measure the projected planet- host separation with a precision of O(10au). At the present time, the balance of evidence favors the unbound-planet hypothesis.
2847. I-band LC of the microlensing event KMT-2016-BLG-1836
ID:
ivo://CDS.VizieR/J/AJ/159/98
Title:
I-band LC of the microlensing event KMT-2016-BLG-1836
Short Name:
J/AJ/159/98
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of a super-Jovian planet in the microlensing event KMT-2016-BLG-1836, which was found by the Korea Microlensing Telescope Network (KMTNet) high-cadence observations ({Gamma}~4/hr). The planet-host mass ratio q~0.004. A Bayesian analysis indicates that the planetary system is composed of a super-Jovian M_planet_=2.2_-1.1_^+1.9^M_J_ planet orbiting an M or K dwarf, M_host_=0.49_-0.25_^+0.38^M_{sun}_, at a distance of D_L_=7.1_-2.4_^+0.8^kpc. The projected planet-host separation is 3.5_-0.9_^+1.1^au, implying that the planet is located beyond the snow line of the host star. Future high-resolution images can potentially strongly constrain the lens brightness and thus the mass and distance of the planetary system. Without considering detailed detection efficiency, selection, or publication biases, we find a potential mass-ratio desert at -3.7<~logq<~-3.0 for the 31 published KMTNet planets.
2848. I-band light curve of KMT-2016-BLG-2605 with KMTNet
ID:
ivo://CDS.VizieR/J/AJ/162/96
Title:
I-band light curve of KMT-2016-BLG-2605 with KMTNet
Short Name:
J/AJ/162/96
Date:
11 Mar 2022 14:37:06
Publisher:
CDS
Description:
With a planet-host mass ratio q=0.012{+/-}0.001, KMT-2016-BLG-2605 has the shortest Einstein timescale, tE=3.41{+/-}0.13days, of any planetary microlensing event to date. This prompts us to examine the full sample of seven short (tE<7days) planetary events with good q measurements. We find that six have clustered Einstein radii {theta}E=115{+/-}20{mu}as and lens-source relative proper motions {mu}rel~9.5{+/-}2.5mas/yr. For the seventh, these two quantities could not be measured. These distributions are consistent with a Galactic bulge population of very low mass (VLM) hosts near the hydrogen-burning limit. This conjecture could be verified by imaging at first adaptive optics light on next-generation (30m) telescopes. Based on a preliminary assessment of the sample, "planetary" companions (i.e., below the deuterium-burning limit) are divided into "genuine planets," formed in their disks by core accretion, and VLM brown dwarfs, which form like stars. We discuss techniques for expanding the sample, which include taking account of the peculiar "anomaly-dominated" morphology of the KMT-2016-BLG-2605 light curve.
2849. I-band light curve of OGLE-2019-BLG-1058 with KMTNet
ID:
ivo://CDS.VizieR/J/AJ/162/267
Title:
I-band light curve of OGLE-2019-BLG-1058 with KMTNet
Short Name:
J/AJ/162/267
Date:
25 Mar 2022 06:06:33
Publisher:
CDS
Description:
We show that because the conditions for producing terrestrial microlens parallax (TPRX; i.e., a nearby disk lens) will also tend to produce a large lens-source relative proper motion ({mu}rel), source proper motion ({mu}S) measurements in general provide a strong test of TPRX signals, which Gould & Yee (2013) showed were an important probe of free-floating planet (FFP) candidates. As a case study, we report a single-lens/single-source microlensing event designated as OGLE-2019-BLG-1058. For this event, the short timescale (~2.5days) and very fast {mu}rel (~17.6mas/yr) suggest that this isolated lens is an FFP candidate located in the disk of our Galaxy. For this event, we find a TPRX signal consistent with a disk FFP, but at low significance. A direct measurement of the {mu}S shows that the large {mu}rel is due to an extreme {mu}S, and thus, the lens is consistent with being a very-low-mass star in the bulge and the TPRX measurement is likely spurious. By contrast, we show how a precise measurement of {mu}S with the mean properties of the bulge proper motion distribution would have given the opposite result; i.e., provided supporting evidence for an FFP in the disk and the TPRX measurement.
2850. I-band light curves of OGLE-2015-BLG-1771Lb
ID:
ivo://CDS.VizieR/J/AJ/159/116
Title:
I-band light curves of OGLE-2015-BLG-1771Lb
Short Name:
J/AJ/159/116
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery and the analysis of the short (t_E_<5days) planetary microlensing event, OGLE-2015-BLG-1771. The event was discovered by the Optical Gravitational Lensing Experiment, and the planetary anomaly (at I~19) was captured by The Korea Microlensing Telescope Network. The event has three surviving planetary models that explain the observed light curves, with planet-host mass ratio q~5.4x10^-3^, 4.5x10^-3^ and 4.5x10^-2^, respectively. The first model is the best-fit model, while the second model is disfavored by {Delta}_{chi}^2^_~3. The last model is strongly disfavored by {Delta}_{chi}^2^_~15 but not ruled out. A Bayesian analysis using a Galactic model indicates that the first two models are probably composed of a Saturn-mass planet orbiting a late M dwarf, while the third one could consist of a super-Jovian planet and a mid-mass brown dwarf. The source-lens relative proper motion is {mu}_rel_~9mas/yr, so the source and lens could be resolved by current adaptive-optics instruments in 2020 if the lens is luminous.