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21441. ULX sources and FIRST radio sources
ID:
ivo://CDS.VizieR/J/A+A/452/739
Title:
ULX sources and FIRST radio sources
Short Name:
J/A+A/452/739
Date:
21 Oct 2021
Publisher:
CDS
Description:
We search for ultra luminous X-ray source (ULXs) radio counterparts located in nearby galaxies in order to constrain their physical nature. Our work is based on a systematic cross-identification of the most recent and extensive available ULX catalogues and archival radio data. A catalogue of 70 positional coincidences is reported. Most of them are located within the galaxy nucleus. Among them, we find 11 new cases of non-nuclear ULX sources with possibly associated radio emission.
21442. ULXs with multiepoch Spitzer/IRAC obs.
ID:
ivo://CDS.VizieR/J/ApJ/878/71
Title:
ULXs with multiepoch Spitzer/IRAC obs.
Short Name:
J/ApJ/878/71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a mid-infrared (IR) sample study of nearby ultraluminous X-ray sources (ULXs) using multiepoch observations with the Infrared Array Camera (IRAC) on the Spitzer Space Telescope. Spitzer/IRAC observations taken after 2014 were obtained as part of the Spitzer Infrared Intensive Transients Survey. Our sample includes 96 ULXs located within 10 Mpc. Of the 96 ULXs, 12 have candidate counterparts consistent with absolute mid-IR magnitudes of supergiants, and 16 counterparts exceeded the mid-IR brightness of single supergiants and are thus more consistent with star clusters or non-ULX background active galactic nuclei. The supergiant candidate counterparts exhibit a bimodal color distribution in a Spitzer/IRAC color-magnitude diagram, where "red" and "'blue" ULXs fall in IRAC colors [3.6]-[4.5]~0.7 and [3.6]-[4.5]~0.0, respectively. The mid-IR colors and absolute magnitudes of four "red" and five "blue" ULXs are consistent with those of supergiant B[e] (sgB[e]) and red supergiant (RSG) stars, respectively. Although "blue," RSG-like mid-IR ULX counterparts likely host RSG mass donors; we propose that "red" counterparts are ULXs exhibiting the "B[e] phenomenon" rather than hosts of sgB[e] mass donors. We show that the mid-IR excess from the "red" ULXs is likely due to thermal emission from circumstellar or circumbinary dust. Using dust as a probe for total mass, we estimate mass-loss rates of dM/dt~1x10^-4^M_{sun}_/yr in dust-forming outflows of red ULXs. Based on the transient mid-IR behavior and its relatively flat spectral index, {alpha}=-0.19+/-0.1, we suggest that the mid-IR emission from Holmberg IX X-1 originates from a variable jet.
21443. ULYSSES supplement to GRB 3B catalog
ID:
ivo://CDS.VizieR/J/ApJS/120/399
Title:
ULYSSES supplement to GRB 3B catalog
Short Name:
J/ApJS/120/399
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present interplanetary network localization information for 218 gamma-ray bursts in the third BATSE catalog obtained by analyzing the arrival times of these bursts with the Ulysses and Compton Gamma Ray Observatory spacecraft. For any given burst observed by these two spacecraft, arrival time analysis (or "triangulation") results in an annulus of possible arrival directions whose half-width varies between 7'' and 32', depending on the intensity and time history of the burst and the distance of the Ulysses spacecraft from Earth. This annulus generally intersects the BATSE error circle, which results in an average reduction of a factor of 30 of the error box area.
21444. UMa Group
ID:
ivo://CDS.VizieR/J/AJ/105/226
Title:
UMa Group
Short Name:
J/AJ/105/226
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Ursa Major Group (UMaG) is studied as a test case for the authenticity of Stellar Kinematic Groups, using Coravel radial velocities, recent compilations of astrometric data and new spectroscopic observations. Spectroscopic age indicators, particularly indices of the strength of chromospheric emission, are applied to solar-type candidate members of UMaG, and it is shown that stars that meet the spectroscopic criteria also have kinematics that agree better with the space motions of the nucleus of UMaG than does the starting sample as a whole. The primary limitation on the precision of kinematics is now parallaxes instead of radial velocities. These more restrictive kinematic criteria are then applied to other UMaG candidates and a list summarizing membership is presented. UMaG is also examined as a cluster, confirming its traditional age of 0.3 Gyr and a mean [Fe/H] of -0.08 +/- 0.09 for those stars most likely to be bona fide members.
21445. 15um AKARI observations in CDFS field
ID:
ivo://CDS.VizieR/J/PASJ/61/177
Title:
15um AKARI observations in CDFS field
Short Name:
J/PASJ/61/177
Date:
21 Oct 2021
Publisher:
CDS
Description:
Deep observations of the Chandra Deep Field South have been secured at 15um with AKARI/IRC infrared space telescope. From these observations, we define a sample of mid infrared-selected galaxies at 15um and we also obtain 15um flux densities for a sample of Lyman Break Galaxies at z~1 already observed at 24um with Spitzer/MIPS.
21446. 55 UMa spectroscopic orbit
ID:
ivo://CDS.VizieR/J/A+A/309/521
Title:
55 UMa spectroscopic orbit
Short Name:
J/A+A/309/521
Date:
21 Oct 2021
Publisher:
CDS
Description:
The first investigation of the known triple system 55 UMa (2.55d binary in a ~1870-d orbit with the third star) based on electronic spectra led to several new findings about the system: (1) Discovery of spectral lines of the tertiary and an unambiguous detection of the lines of the secondary. Spectra of both primary and tertiary are of the same strength and correspond to spectral class A0V. The secondary spectrum is about twice fainter in the visual region and belongs probably also to spectral class A. (2) First self-consistent orbital solution describing close and wide orbit and the detection of apsidal motion for the close pair. The orbital period of the close pair was improved to (2.5538380+/-0.0000046d) and basic physical elements for all three stars and the system were estimated. The orbital solution also gives the period of apsidal motion of the close pair of (450+/-60)yr and leads to a good agreement with the published speckle-interferometric orbit for the distant companion if the longitude of periastron passage is increased by 180deg.
21447. 84 UMa ubvy photometry
ID:
ivo://CDS.VizieR/J/A+A/335/973
Title:
84 UMa ubvy photometry
Short Name:
J/A+A/335/973
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new longitudinal magnetic field and Stroemgren photometric measurements of the Bp star 84 UMa. From these data we determine a new rotational period P_rot_=1.38576+/-0.00080d, which is inconsistent with previously published values. The magnetic measurements indicate the presence of a weak, dominantly dipolar magnetic field in the photosphere of 84 UMa. We employ a new value of the rotational axis inclination in conjunction with the magnetic data in order to constrain the magnetic field geometry. We derive the following dipole oblique rotator parameters: i=59^+17^_-9_{deg}, {beta}=48^+17^_-29_{deg}, and B_d_=1620^+1270^_-30_G. A precise value of the radius (which we calculate in conjunction with the inclination using the Hipparcos parallax) allows us to locate 84 UMa on the radius-effective temperature plane. Using theoretical evolutionary tracks (Schaller et al., 1992, Cat. <J/A+AS/96/269>), we obtain values for the mass, age and surface gravity. These results place 84 UMa quite close to the ZAMS, a result inconsistent with the suggestion by Hubrig & Mathys (1994AN....315..343H) that the magnetic Ap stars may be near the end of their main sequence life.
21448. 8um Cores in NGC 891, NGC 3628 and IC 5052
ID:
ivo://CDS.VizieR/J/ApJ/895/71
Title:
8um Cores in NGC 891, NGC 3628 and IC 5052
Short Name:
J/ApJ/895/71
Date:
11 Mar 2022
Publisher:
CDS
Description:
To study the vertical distribution of the earliest stages of star formation in galaxies, three edge-on spirals, NGC891, NGC3628, and IC5052, observed by the Spitzer Space Telescope InfraRed Array Camera (IRAC) were examined for compact 8{mu}m cores using an unsharp mask technique; 173, 267, and 60 cores were distinguished, respectively. Color-color distributions suggest a mixture of polycyclic aromatic hydrocarbons and highly extincted photospheric emission from young stars. The average V-band extinction is ~20mag, equally divided between foreground and core. IRAC magnitudes for the clumps are converted to stellar masses assuming an age of 1Myr, which is about equal to the ratio of the total core mass to the star formation rate in each galaxy. The extinction and stellar mass suggest an intrinsic core radius of ~18pc for 5% star formation efficiency. The half-thickness of the disk of 8{mu}m cores is 105pc for NGC891 and 74pc for IC5052, varying with radius by a factor of ~2. For NGC3628, which is interacting, the half-thickness is 438pc, but even with this interaction, the 8{mu}m disk is remarkably flat, suggesting vertical stability. Small-scale structures like shingles or spirals are seen in the core positions. Very few of the 8{mu}m cores have optical counterparts.
21449. 8um cores in the spiral arms of nearby galaxies
ID:
ivo://CDS.VizieR/J/ApJS/245/14
Title:
8um cores in the spiral arms of nearby galaxies
Short Name:
J/ApJS/245/14
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spitzer Space Telescope observations of 15 spiral galaxies show numerous dense cores at 8{mu}m that are revealed primarily in unsharp mask images. The cores are generally invisible in optical bands because of extinction, and they are also indistinct at 8{mu}m alone because of contamination by more widespread diffuse emission. Several hundred core positions, magnitudes, and colors from the four InfraRed Array Camera bands are measured and tabulated for each galaxy. The larger galaxies, which tend to have longer and more regular spiral arms, often have their infrared cores aligned along these arms, with additional cores in spiral arm spurs. Galaxies without regular spirals have their cores in more irregular spiral-like filaments, with typically only one or two cores per filament. Nearly every elongated emission feature has 8{mu}m cores strung out along its length. The occurrence of dense cores in long and thin filaments is reminiscent of filamentary star formation in the solar neighborhood, although on a scale 100 times larger in galaxies. The cores most likely form by gravitational instabilities and cloud agglomeration in the filaments. The simultaneous occurrence of several cores with regular spacings in some spiral arms suggests that in these cases, all of the cores formed at about the same time and the corresponding filaments are young. Total star formation rates for the galaxies correlate with the total embedded stellar masses in the cores with an average ratio corresponding to a possible age between 0.2 and 2Myr. This suggests that the identified cores are the earliest phase for most star formation.
21450. 24um excesses in clusters & membership of NGC2244
ID:
ivo://CDS.VizieR/J/ApJ/836/34
Title:
24um excesses in clusters & membership of NGC2244
Short Name:
J/ApJ/836/34
Date:
21 Oct 2021
Publisher:
CDS
Description:
We characterize the first 40 Myr of evolution of circumstellar disks through a unified study of the infrared properties of members of young clusters and associations with ages from 2Myr up to ~40Myr: NGC1333, NGC1960, NGC2232, NGC2244, NGC2362, NGC2547, IC348, IC2395, IC4665, ChamaeleonI, OrionOB1a and OB1b, Taurus, the {beta} Pictoris Moving Group, {rho} Ophiuchi, and the associations of Argus, Carina, Columba, Scorpius-Centaurus, and Tucana-Horologium. Our work features: (1) a filtering technique to flag noisy backgrounds; (2) a method based on the probability distribution of deflections, P(D), to obtain statistically valid photometry for faint sources; and (3) use of the evolutionary trend of transitional disks to constrain the overall behavior of bright disks. We find that the fraction of disks three or more times brighter than the stellar photospheres at 24{mu}m decays relatively slowly initially and then much more rapidly by ~10Myr. However, there is a continuing component until ~35Myr, probably due primarily to massive clouds of debris generated in giant impacts during the oligarchic/chaotic growth phases of terrestrial planets. If the contribution from primordial disks is excluded, the evolution of the incidence of these oligarchic/chaotic debris disks can be described empirically by a log-normal function with the peak at 12-20Myr, including ~13% of the original population, and with a post-peak mean duration of 10-20Myr.

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