- ID:
- ivo://CDS.VizieR/J/MNRAS/491/5524
- Title:
- Discovering Large-Scale Structure in ORELSE Survey
- Short Name:
- J/MNRAS/491/5524
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey is an ongoing imaging and spectroscopic campaign initially designed to study the effects of environment on galaxy evolution in high-redshift (z~1) large-scale structures. We use its rich data in combination with a powerful new technique, Voronoi tessellation Monte-Carlo (VMC) mapping, to search for serendipitous galaxy overdensities at 0.55<z<1.37 within 15 ORELSE fields, a combined spectroscopic footprint of ~1.4 square degrees. Through extensive tests with both observational data and our own mock galaxy catalogs, we optimize the method's many free parameters to maximize its efficacy for general overdensity searches. Our overdensity search yielded 402 new overdensity candidates with precisely measured redshifts and an unprecedented sensitivity down to low total overdensity masses M_tot_>5*10^13^M_{sun}_). Using the mock catalogs, we estimated the purity and completeness of our overdensity catalog as a function of redshift, total mass, and spectroscopic redshift fraction, finding impressive levels of both 0.92/0.83 and 0.60/0.49 for purity/completeness at z=0.8 and z=1.2, respectively, for all overdensity masses at spectroscopic fractions of ~20%. With VMC mapping, we are able to measure precise systemic redshifts, provide an estimate of the total gravitating mass, and maintain high levels of purity and completeness at z~1 even with only moderate levels of spectroscopy. Other methods (e.g., red-sequence overdensities and hot medium reliant detections) begin to fail at similar redshifts, which attests to VMC mapping's potential to be a powerful tool for current and future wide-field galaxy evolution surveys at z~1 and beyond.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/624/A87
- Title:
- Discovery of a resolved disk around Wray 15-788
- Short Name:
- J/A+A/624/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Protoplanetary disks are the birth environments of planetary systems. Therefore, the study of young, circumstellar environments is essential to understanding the processes taking place in planet formation and the evolution of planetary systems. We detect and characterize circumstellar disks and potential companions around solar-type, pre-main sequence stars in the Scorpius-Centaurus association (Sco-Cen). As part of our ongoing survey we carried out high-contrast imaging with VLT/SPHERE/IRDIS to obtain polarized and total intensity images of the young (11^+16^_-7_)Myr old) K3IV star Wray 15-788 within the Lower Centaurus Crux subgroup of Sco-Cen. For the total intensity images, we remove the stellar halo via an approach based on reference star differential imaging in combination with principal component analysis. Both total intensity and polarimetric data resolve a disk around the young, solar-like Sco-Cen member Wray 15-788. Modeling of the stellar spectral energy distribution suggests that this is protoplanetary disk at a transition stage. We detect a bright outer ring at a projected separation of ~370mas (~56au), hints of inner substructures at ~170mas (~28au), and a gap in between. Within a position angle range of only 60{deg}<{phi}<240{deg}, we are confident at the 5{sigma} level that we detect actual scattered light flux from the outer ring of the disk; the remaining part is indistinguishable from background noise. For the detected part of the outer ring we determine a disk inclination of i=21{deg}+/-6{deg} and a position angle of {varphi}=76{deg}+/-16{deg}. Furthermore, we find that Wray 15-788 is part of a binary system with the A2V star HD 98363 at a separation of ~50arcsec (~6900,au). The detection of only half of the outer ring might be due to shadowing by a misaligned inner disk. A potential substellar companion can cause the misalignment of the inner structures and can be responsible for clearing the detected gap from scattering material.However, we cannot rule out the possibility of a non-detection due to our limited signal-to-noise ratio, combined with brightness azimuthal asymmetry. From our data we can exclude companions more massive than 10M_{jup}_ within the gap at a separation of ~230mas (~35au). Additional data are required to characterize the disk's peculiar morphology and to set tighter constraints on the potential perturber's orbital parameters and mass.
3783. Discovery of PNe in M82
- ID:
- ivo://CDS.VizieR/J/ApJ/697/1138
- Title:
- Discovery of PNe in M82
- Short Name:
- J/ApJ/697/1138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using an [OIII]{lambda}5007 on-band/off-band filter technique, we identify 109 planetary nebulae (PNe) candidates in the edge-on spiral galaxy M 82, using the FOCAS instrument at the 8.2m Subaru Telescope. The use of ancillary high-resolution Hubble Space Telescope Advanced Camera for Surveys H{alpha} imaging aided in confirming these candidates, helping to discriminate PNe from contaminants such as supernova remnants and compact HII regions. Once identified, these PNe reveal a great deal about the host galaxy; our analysis covers kinematics, stellar distribution, and distance determination. Radial velocities were determined for 94 of these PNe using a method of slitless spectroscopy, from which we obtain a clear picture of the galaxy's rotation.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A73
- Title:
- Discovery of the directly imaged planet YSES 2b
- Short Name:
- J/A+A/648/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To understand the origin and formation pathway of wide-orbit gas giant planets, it is necessary to expand the limited sample of these objects. The mass of exoplanets derived with spectrophotometry, however, varies strongly as a function of the age of the system and the mass of the primary star. By selecting stars with similar ages and masses, the Young Suns Exoplanet Survey (YSES) aims to detect and characterize planetary-mass companions to solar-type host stars in the Scorpius-Centaurus association. Our survey is carried out with VLT/SPHERE with short exposure sequences on the order of 5-min per star per filter. The subtraction of the stellar point spread function (PSF) is based on reference star differential imaging (RDI) using the other targets (with similar colors and magnitudes) in the survey in combination with principal component analysis. Two astrometric epochs that are separated by more than one year are used to confirm co-moving companions by proper motion analysis. We report the discovery of YSES 2b, a co-moving, planetary-mass companion to the K1 star YSES 2 (TYC 8984-2245-1, 2MASS J11275535-6626046). The primary has a Gaia EDR3 distance of 110pc, and we derive a revised mass of 1.1M_{sun}_ and an age of approximately 14Myr. We detect the companion in two observing epochs southwest of the star at a position angle of 205{deg} and with a separation of ~1.05", which translates to a minimum physical separation of 115au at the distance of the system. Photometric measurements in the H and Ks bands are indicative of a late L spectral type, similar to the innermost planets around HR 8799. We derive a photometric planet mass of 6.3^+1.6^_-0.9_M_{Jup}_ using AMES-COND and AMES-dusty evolutionary models; this mass corresponds to a mass ratio of q=(0.5+/-0.1)% with the primary. This is the lowest mass ratio of a direct imaging planet around a solar-type star to date. We discuss potential formation mechanisms and find that the current position of the planet is compatible with formation by disk gravitational instability, but its mass is lower than expected from numerical simulations. Formation via core accretion must have occurred closer to the star, yet we do not find evidence that supports the required outward migration, such as via scattering off another undiscovered companion in the system. We can exclude additional companions with masses greater than 13M_{Jup}_ in the full field of view of the detector (0.15"<{rho}<5.50"), at 0.5" we can rule out further objects that are more massive than 6M_{Jup}_, and for projected separations {rho}>2arcsec we are sensitive to planets with masses as low as 2M_{Jup}_. YSES 2b is an ideal target for follow-up observations to further the understanding of the physical and chemical formation mechanisms of wide-orbit Jovian planets. The YSES strategy of short snapshot observations (<=5min) and PSF subtraction based on a large reference library proves to be extremely efficient and should be considered for future direct imaging surveys.
- ID:
- ivo://CDS.VizieR/J/ApJ/734/98
- Title:
- DISCS. II. Southern sky disk data
- Short Name:
- J/ApJ/734/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second in a series of papers based on data from DISCS, a Submillimeter Array observing program aimed at spatially and spectrally resolving the chemical composition of 12 protoplanetary disks. We present data on six Southern sky sources -IM Lup, SAO 206462 (HD 135344b), HD 142527, AS 209, AS 205, and V4046 Sgr- which complement the six sources in the Taurus star-forming region reported previously. CO 2-1 and HCO^+^ 3-2 emission are detected and resolved in all disks and show velocity patterns consistent with Keplerian rotation. Where detected, the emission from DCO^+^ 3-2, N_2_H^+^ 3-2, H_2_CO 3_0 3_-2_0 2_ and 4_1 4_-3_1 3_, HCN 3-2, and CN 2_3 3/4/2_-1_2 2/3/1_ are also generally spatially resolved. The detection rates are highest toward the M and K stars, while the F star SAO 206462 has only weak CN and HCN emission, and H2CO alone is detected toward HD 142527.
- ID:
- ivo://CDS.VizieR/J/MNRAS/492/L40
- Title:
- Disentangling cataclysmic variables in Gaia DR2
- Short Name:
- J/MNRAS/492/L40
- Date:
- 07 Dec 2021 09:36:41
- Publisher:
- CDS
- Description:
- Cataclysmic Variables (CVs) are interacting binaries consisting of at least three components that control their colour and magnitude. Using Gaia we here investigate the influence of the physical properties of these binaries on their position in the Hertzsprung-Russell diagram (HR-diagram). The CVs are on average located between the main sequence and the white dwarf regime, the maximum density being at G_BP_-G_RP_~=0.56 and G_abs_~10.15. We nd a trend of the orbital period with colour and absolute brightness: with decreasing period, the CVs become bluer and fainter. We also identify the location of the various CV sub-types in the HR-diagram and discuss the possible location of detached CVs, going through the orbital period gap.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A104
- Title:
- Disk and halo stars C, O and Fe abundances
- Short Name:
- J/A+A/630/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The abundances of carbon, oxygen, and iron in late-type stars are important parameters in exoplanetary and stellar physics, as well as key tracers of stellar populations and Galactic chemical evolution. However, standard spectroscopic abundance analyses can be prone to severe systematic errors, by the assumption that the stellar atmosphere is one-dimensional (1D) and hydrostatic, and by ignoring departures from local thermodynamic equilibrium (LTE). To address this, we carry out 3D non-LTE radiative transfer calculations for CI and OI, and 3D LTE radiative transfer calculations for FeII, across the stagger-grid of 3D hydrodynamic model atmospheres. The absolute 3D non-LTE versus 1D LTE abundance corrections can be as severe as ~0.3dex for CI lines in low-metallicity F dwarfs, and ~0.6dex for OI lines in high-metallicity F dwarfs. The 3D LTE versus 1D LTE abundance corrections for FeII lines are less severe, typically less than +0.15dex. We use the corrections in a re-analysis of carbon, oxygen, and iron in 187 F and G dwarfs in the Galactic disk and halo. Applying the differential 3D non-LTE corrections to 1D LTE abundances visibly reduces the scatter in the abundance plots. The thick disk and high- halo population rise in carbon and oxygen with decreasing metallicity, reaching a maximum of [C/Fe]~=0.2 and a plateau of [O/Fe]~=0.6 at [Fe/H]~=~1.0. The low- halo population is qualitatively similar, albeit offset towards lower metallicities and with larger scatter. Nevertheless, these populations overlap in the [C/O] versus [O/H] plane, decreasing to a plateau of [C/O]~=0.6 below [O/H]~=1.0. In the thin-disk, stars having confirmed planet detections tend to have higher values of C/O at given [O/H]; this potential signature of planet formation is only apparent after applying the abundance corrections to the 1D LTE results. Our grids of line-by-line abundance corrections are publicly available and can readily be used to improve the accuracy of spectroscopic analyses of late-type stars.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A149
- Title:
- Disk and halo stars C, O and Fe abundances (Amarsi+, 2019)
- Short Name:
- J/A+A/630/A149
- Date:
- 27 Sep 2019 05:42:26
- Publisher:
- CDS
- Description:
- Spectrum synthesis calculations were performed on four different families of model atmospheres: 3D hydrodynamic model atmospheres from the STAGGER-grid (Magic et al. 2013A&A...557A..26M, Cat. J/A+A/557/A26); 1D model atmospheres determined by averaging the <3D> STAGGER model atmospheres (henceforth <3D> model atmospheres; Magic et al. 2013A&A...560A...8M, Cat. J/A+A/560/A8); theoretical 1D hydrostatic model atmospheres from the ATMO-grid (the 1D equivalent of the STAGGER-grid, see Appendix A of Magic et al. 2013A&A...557A..26M, Cat. J/A+A/557/A26); and theoretical 1D hydrostatic model atmospheres from the MARCS-grid (Gustafsson et al. 2008A&A...486..951G). Table1 contains the line parameters that were adopted for the grids of abundance corrections. Table2 contains the 3D non-LTE versus 1D LTE abundance corrections for CI lines. Table3 contains the 3D non-LTE versus 1D LTE abundance corrections for OI lines. Table4 contains the 3D LTE versus 1D LTE abundance corrections for FeII lines. Table5 contains the 1D non-LTE versus 1D LTE abundance corrections for CI lines. Table6 contains the 1D non-LTE versus 1D LTE abundance corrections for OI lines. Table7 contains the stellar parameters and abundances for the 187 sample stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/773/135
- Title:
- Disk-bearing stars in Cygnus OB2
- Short Name:
- J/ApJ/773/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The formation of stars in massive clusters is one of the main modes of the star formation process. However, the study of massive star-forming regions is hampered by their typically large distances to the Sun. One exception to this is the massive star-forming region Cygnus OB2 in the Cygnus X region, at the distance of ~1400pc. Cygnus OB2 hosts very rich populations of massive and low-mass stars, being the best target in our Galaxy to study the formation of stars, circumstellar disks, and planets in the presence of massive stars. In this paper, we combine a wide and deep set of photometric data, from the r band to 24{mu}m, in order to select the disk-bearing population of stars in Cygnus OB2 and identify the class I, class II, and stars with transition and pre-transition disks. We selected 1843 sources with infrared excesses in an area of 1{deg}x1{deg} centered on Cyg OB2 in several evolutionary stages: 8.4% class I, 13.1% flat-spectrum sources, 72.9% class II, 2.3% pre-transition disks, and 3.3% transition disks. The spatial distribution of these sources shows a central cluster surrounded by an annular overdensity and some clumps of recent star formation in the outer region. Several candidate subclusters are identified, both along the overdensity and in the rest of the association.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2085
- Title:
- Disk brightness profiles in galaxies
- Short Name:
- J/AJ/127/2085
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the disk brightness profiles of 218 spiral and lenticular galaxies. At least 28% of disk galaxies exhibit inner truncations in these profiles. There are no significant trends of truncation incidence with Hubble type, but the incidence among barred systems is 49%, more than 4 times that for non-barred galaxies. However, not all barred systems have inner truncations, and not all inner-truncated systems are currently barred. Truncations represent a real dearth of disk stars in the inner regions and are not an artifact of our selection or fitting procedures nor the result of obscuration by dust.