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2861. Circumstellar disks in the Upper Sco association
ID:
ivo://CDS.VizieR/J/AJ/156/75
Title:
Circumstellar disks in the Upper Sco association
Short Name:
J/AJ/156/75
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have performed a survey for new members of the Upper Sco association that have circumstellar disks using mid-infrared photometry from the Wide-field Infrared Survey Explorer (WISE). Through optical and near-infrared spectroscopy, we have confirmed 185 candidates as likely members of Upper Sco with spectral types ranging from mid-K to M9. They comprise ~36% of the known disk-bearing members of the association. We also have compiled all available mid-infrared photometry from WISE and the Spitzer Space Telescope for the known members of Upper Sco, resulting in a catalog of data for 1608 objects. We have used these data to identify the members that exhibit excess emission from disks and we have classified the evolutionary stages of those disks with criteria similar to those applied in our previous studies of Taurus and Upper Sco. Among 484 members with excesses in at least one band (excluding five Be stars), we classify 296 disks as full, 66 as evolved, 19 as transitional, 22 as evolved or transitional, and 81 as evolved transitional or debris. Many of these disks have not been previously reported, including 129 full disks and 50 disks that are at more advanced evolutionary stages.
2862. Circumstellar disks in Trapezium cluster
ID:
ivo://CDS.VizieR/J/A+A/441/195
Title:
Circumstellar disks in Trapezium cluster
Short Name:
J/A+A/441/195
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present results on the size distribution of circumstellar disks in the Trapezium cluster as measured from HST/WFPC2 data. Direct diameter measurements of a sample of 135 bright proplyds and 14 silhouettes disks suggest that there is a single population of disks well characterized by a power-law distribution with an exponent of -1.9+/-0.3 between disk diameters 100-400AU. For the stellar mass sampled (from late G to late M stars) we find no obvious correlation between disk diameter and stellar mass. We also find that there is no obvious correlation between disk diameter and the projected distance to the ionizing Trapezium OB stars. We estimate that about 40% of the disks in the Trapezium have radius larger than 50AU. We suggest that the origin of the Solar system's (Kuiper belt) outer edge is likely to be due to the star formation environment and disk destruction processes (photo-evaporation, collisions) present in the stellar cluster on which the Sun was probably formed. Finally, we identified a previously unknown proplyd and named it 266-557, following convention.
2863. Circumstellar dust of 104 stars with GPIES
ID:
ivo://CDS.VizieR/J/AJ/160/24
Title:
Circumstellar dust of 104 stars with GPIES
Short Name:
J/AJ/160/24
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of a ~4yr direct imaging survey of 104 stars to resolve and characterize circumstellar debris disks in scattered light as part of the Gemini Planet Imager (GPI) Exoplanet Survey. We targeted nearby (<~150pc), young (<~500Myr) stars with high infrared (IR) excesses (LIR/L_{star}_>10^-5^), including 38 with previously resolved disks. Observations were made using the GPI high-contrast integral field spectrograph in H-band (1.6{mu}m) coronagraphic polarimetry mode to measure both polarized and total intensities. We resolved 26 debris disks and 3 protoplanetary/transitional disks. Seven debris disks were resolved in scattered light for the first time, including newly presented HD117214 and HD156623, and we quantified basic morphologies of five of them using radiative transfer models. All of our detected debris disks except HD156623 have dust-poor inner holes, and their scattered-light radii are generally larger than corresponding radii measured from resolved thermal emission and those inferred from spectral energy distributions. To assess sensitivity, we report contrasts and consider causes of nondetections. Detections were strongly correlated with high IR excess and high inclination, although polarimetry outperformed total intensity angular differential imaging for detecting low-inclination disks (<~70{deg}). Based on postsurvey statistics, we improved upon our presurvey target prioritization metric predicting polarimetric disk detectability. We also examined scattered-light disks in the contexts of gas, far-IR, and millimeter detections. Comparing H-band and ALMA fluxes for two disks revealed tentative evidence for differing grain properties. Finally, we found no preference for debris disks to be detected in scattered light if wide-separation substellar companions were present.
2864. Circumstellar emission measures with Keck
ID:
ivo://CDS.VizieR/J/ApJ/734/67
Title:
Circumstellar emission measures with Keck
Short Name:
J/ApJ/734/67
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Keck Interferometer Nuller (KIN) was used to survey 25 nearby main-sequence stars in the mid-infrared, in order to assess the prevalence of warm circumstellar (exozodiacal) dust around nearby solar-type stars. The KIN measures circumstellar emission by spatially blocking the star but transmitting the circumstellar flux in a region typically 0.1-4AU from the star. We find one significant detection ({eta} Crv), two marginal detections ({gamma} Oph and {alpha} Aql), and 22 clear non-detections. Using a model of our own solar system's zodiacal cloud, scaled to the luminosity of each target star, we estimate the equivalent number of target zodis needed to match our observations. Our three zodi detections are {eta} Crv (1250+/-260), {gamma} Oph (200+/-80), and {alpha} Aql (600+/-200), where the uncertainties are 1{sigma}. The 22 non-detected targets have an ensemble weighted average consistent with zero, with an average individual uncertainty of 160 zodis (1{sigma}). These measurements represent the best limits to date on exozodi levels for a sample of nearby main-sequence stars. A statistical analysis of the population of 23 stars not previously known to contain circumstellar dust (excluding {eta} Crv and {gamma} Oph) suggests that, if the measurement errors are uncorrelated (for which we provide evidence) and if these 23 stars are representative of a single class with respect to the level of exozodi brightness, the mean exozodi level for the class is <150 zodis (3{sigma} upper limit, corresponding to 99% confidence under the additional assumption that the measurement errors are Gaussian). We also demonstrate that this conclusion is largely independent of the shape and mean level of the (unknown) true underlying exozodi distribution.
2865. Circumstellar-interacting supernovae
ID:
ivo://CDS.VizieR/J/A+A/580/A131
Title:
Circumstellar-interacting supernovae
Short Name:
J/A+A/580/A131
Date:
21 Oct 2021
Publisher:
CDS
Description:
Some circumstellar-interacting (CSI) supernovae (SNe) are produced by the explosions of massive stars that have lost mass shortly before the SN explosion. There is evidence that the precursors of some SNe IIn were luminous blue variable (LBV) stars. For a small number of CSI SNe, outbursts have been observed before the SN explosion. Eruptive events of massive stars are named SN impostors (SN IMs) and whether they herald a forthcoming SN or not is still unclear. The large variety of observational properties of CSI SNe suggests the existence of other progenitors, such as red supergiant (RSG) stars with superwinds. Furthermore, the role of metallicity in the mass loss of CSI SN progenitors is still largely unexplored. Our goal is to gain insight into the nature of the progenitor stars of CSI SNe by studying their environments, in particular the metallicity at their locations. We obtain metallicity measurements at the location of 60 transients (including SNe IIn, SNe Ibn, and SN IMs) via emission-line diagnostic on optical spectra obtained at the Nordic Optical Telescope and through public archives. Metallicity values from the literature complement our sample. We compare the metallicity distributions among the different CSI SN subtypes, and to those of other core-collapse SN types. We also search for possible correlations between metallicity and CSI SN observational properties. We find that SN IMs tend to occur in environments with lower metallicity than those of SNe IIn. Among SNe IIn, SN IIn-L(1998S-like) SNe show higher metallicities, similar to those of SNe IIL/P, whereas long-lasting SNe IIn (1988Z-like) show lower metallicities, similar to those of SN IMs. The metallicity distribution of SNe IIn can be reproduced by combining the metallicity distributions of SN IMs (which may be produced by major outbursts of massive stars like LBVs) and SNe IIP (produced by RSGs). The same applies to the distributions of the normalized cumulative rank (NCR) values, which quantifies the SN association to HII regions. For SNe IIn, we find larger mass-loss rates and higher CSM velocities at higher metallicities. The luminosity increment in the optical bands during SN IM outbursts tend to be larger at higher metallicity, whereas the SN IM quiescent optical luminosities tend to be lower. The difference in metallicity between SNe IIn and SN IMs indicates that LBVs are only one of the progenitor channels for SNe IIn, with 1988Z-like and 1998S-like SNe possibly arising from LBVs and RSGs, respectively. Finally, even though line-driven winds likely do not primarily drive the late mass-loss of CSI SN progenitors, metallicity has some impact on the observational properties of these transients.
2866. CIRS (Cluster Infall Regions in the SDSS). I.
ID:
ivo://CDS.VizieR/J/AJ/132/1275
Title:
CIRS (Cluster Infall Regions in the SDSS). I.
Short Name:
J/AJ/132/1275
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use the Fourth Data Release of the Sloan Digital Sky Survey (SDSS) to test the ubiquity of infall patterns around galaxy clusters and measure cluster mass profiles to large radii. The Cluster and Infall Region Nearby Survey (CAIRNS) found infall patterns in nine clusters, but the cluster sample was incomplete. Here we match X-ray cluster catalogs with SDSS, search for infall patterns, and compute mass profiles for a complete sample of X-ray-selected clusters. Very clean infall patterns are apparent in most of the clusters, with the fraction decreasing with increasing redshift due to shallower sampling. All 72 clusters in a well-defined sample limited by redshift (ensuring good sampling) and X-ray flux (excluding superpositions) show infall patterns sufficient to apply the caustic technique. This sample is by far the largest sample of cluster mass profiles extending to large radii to date. Similar to CAIRNS, cluster infall patterns are better defined in observations than in simulations. Further work is needed to determine the source of this difference. We use the infall patterns to compute mass profiles for 72 clusters and compare them to model profiles. Cluster scaling relations using caustic masses agree well with those using X-ray or virial mass estimates, confirming the reliability of the caustic technique. We confirm the conclusion of CAIRNS that cluster infall regions are well fitted by Navarro-Frenk-White (NFW) and Hernquist profiles and poorly fitted by singular isothermal spheres. This much larger sample enables new comparisons of cluster properties with those in simulations. The shapes (specifically NFW concentrations) of the mass profiles agree well with the predictions of simulations. The mass in the infall region is typically comparable to or larger than that in the virial region. Specifically, the mass inside the turnaround radius is on average 2.19+/-0.18 times that within the virial radius. This ratio agrees well with recent predictions from simulations of the final masses of dark matter halos.
2867. CIV 1549{AA} emission line in AGNs
ID:
ivo://CDS.VizieR/J/ApJ/666/757
Title:
CIV 1549{AA} emission line in AGNs
Short Name:
J/ApJ/666/757
Date:
21 Oct 2021
Publisher:
CDS
Description:
We are exploring a spectroscopic unification for all types of broad-line emitting AGNs. The four-dimensional Eigenvector 1 (4DE1) parameter space organizes quasar diversity in a sequence primarily governed by Eddington ratio. This paper considers the role of CIV {lambda}1549 measures as 4DE1 diagnostics. We use HST archival spectra for 130 sources with S/N high enough to permit reliable CIV {lambda}1549 broad-component measures.
2868. CIV absorption in BAL QSOs
ID:
ivo://CDS.VizieR/J/MNRAS/449/1593
Title:
CIV absorption in BAL QSOs
Short Name:
J/MNRAS/449/1593
Date:
21 Oct 2021
Publisher:
CDS
Description:
There is a large diversity in the CIV broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the CIV BAL properties, full width at half-maximum (FWHM), maximum depth of absorption and its velocity shift (v_md_), using the Sloan Digital Sky Survey DR7 quasar catalogue. We find the following: (i) Although the median CIV BAL profile in the quasar rest-frame becomes broader and shallower as the UV continuum slope ({alpha}UV at 1700-3000{AA}) gets bluer, the median individual profile in the absorber rest-frame remains identical, and is narrow (FWHM=3500km/s) and deep. Only 4 percent of BALs have FWHM>10000km/s. (ii) As the HeII emission equivalent width (EW) decreases, the distributions of FWHM and v_md_ extend to larger values, and the median maximum depth increases. These trends are consistent with theoretical models in which softer ionizing continua reduce overionization, and allow radiative acceleration of faster BAL outflows. (iii) As {alpha}_UV_ becomes bluer, the distribution of v_md_ extends to larger values. This trend may imply faster outflows at higher latitudes above the accretion disc plane. (iv) For non-BALQs, the CIV emission line decreases with decreasing HeII EW, and becomes more asymmetric and blueshifted. This suggests an increasing relative contribution of emission from the BAL outflow to the Civ emission line as the ionizing spectral energy distribution (SED) gets softer, which is consistent with the increasing fraction of BALQs as the ionizing SED gets softer.
2869. CIV absorption in DLAs and sub-DLAs systems
ID:
ivo://CDS.VizieR/J/A+A/473/791
Title:
CIV absorption in DLAs and sub-DLAs systems
Short Name:
J/A+A/473/791
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of CIV absorption in a sample of 63 damped Lyman-{alpha} (DLA) systems and 11 sub-DLAs in the redshift range 1.75<z_abs_<3.61, using a dataset of high-resolution (6.6km/s FWHM), high signal-to-noise VLT/UVES spectra. The complex absorption line profiles show both narrow and broad CIV components, indicating the presence of both warm, photoionized and hot, collisionally ionized gas. We report new correlations between the metallicity (measured in the neutral-phase) and each of the CIV column density, the CIV total line width, and the maximum CIV velocity.
2870. CIV and FeK{alpha} Baldwin effects in AGNs
ID:
ivo://CDS.VizieR/J/ApJ/702/767
Title:
CIV and FeK{alpha} Baldwin effects in AGNs
Short Name:
J/ApJ/702/767
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use UV/optical and X-ray observations of 272 radio-quiet Type 1 active galactic nuclei and quasars to investigate the CIV Baldwin Effect (BEff). The UV/optical spectra are drawn from the Hubble Space Telescope, International Ultraviolet Explorer and Sloan Digital Sky Survey archives. The X-ray spectra are from the Chandra and XMM-Newton archives. We apply correlation and partial-correlation analyses to the equivalent widths (EWs), continuum monochromatic luminosities, and {alpha}_ox_, which characterizes the relative X-ray to UV brightness. The EW of the CIV{lambda}1549 emission line is correlated with both {alpha}_ox_ and luminosity. In our sample, narrow Fe K{alpha} 6.4keV emission lines are detected in 50 objects.

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