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411. Discovering Large-Scale Structure in ORELSE Survey
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.
412. Distant spheroids in the GOODS fields
ID:
ivo://CDS.VizieR/J/ApJ/680/70
Title:
Distant spheroids in the GOODS fields
Short Name:
J/ApJ/680/70
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the first results of a new study aimed at understanding the diversity and evolutionary history of distant galactic bulges in the context of now well-established trends for pure spheroidal galaxies. To this end, bulges have been isolated for a sample of 137 spiral galaxies within the redshift range 0.1<z<1.2 in the GOODS fields. Using proven photometric techniques, we determine the characteristic parameters (size, surface brightness, profile shape) of both the disk and bulge components in our sample. In agreement with earlier work that utilized aperture colors, distant bulges show a broader range of optical colors than would be the case for passively evolving populations. To quantify the amount of recent star formation necessary to explain this result, we used DEIMOS to secure stellar velocity dispersions for a sizeable fraction of our sample. This has enabled us to compare the fundamental plane of our distant bulges with that for spheroidal galaxies in a similar redshift range.
413. 3D kinematic observations of stars in Galactic Centre
ID:
ivo://CDS.VizieR/J/ApJ/779/L6
Title:
3D kinematic observations of stars in Galactic Centre
Short Name:
J/ApJ/779/L6
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present three-dimensional (3D) kinematic observations of stars within the central 0.5pc of the Milky Way (MW) nuclear star cluster (NSC) using adaptive optics imaging and spectroscopy from the Keck telescopes. Recent observations have shown that the cluster has a shallower surface density profile than expected for a dynamically relaxed cusp, leading to important implications for its formation and evolution. However, the true 3D profile of the cluster is unknown due to the difficulty in de-projecting the stellar number counts. Here, we use spherical Jeans modeling of individual proper motions and radial velocities to constrain, for the first time, the de-projected spatial density profile, cluster velocity anisotropy, black hole mass (M_BH_), and distance to the Galactic center (R_0_) simultaneously. We find that the inner stellar density profile of the late-type stars, {rho}(r){prop.to}r^-{gamma}^, have a power law slope {gamma}=0.05_-0.60^+0.29^, much more shallow than the frequently assumed Bahcall-Wolf slope of {gamma}=7/4. The measured slope will significantly affect dynamical predictions involving the cluster, such as the dynamical friction time scale. The cluster core must be larger than 0.5 pc, which disfavors some scenarios for its origin. Our measurement of M_BH_=5.76_-1.26_^+1.76^x10^6^M_{sun}_ and R_0_=8.92_-0.55_^+0.58^kpc is consistent with that derived from stellar orbits within 1" of Sgr A*. When combined with the orbit of S0-2, the uncertainty on R_0_ is reduced by 30% (8.46_-0.38_^+0.42^kpc). We suggest that the MW NSC can be used in the future in combination with stellar orbits to significantly improve constraints on R_0_.
414. DLAs in SDSS-DR7
ID:
ivo://CDS.VizieR/J/A+A/505/1087
Title:
DLAs in SDSS-DR7
Short Name:
J/A+A/505/1087
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of the evolution of the cosmological mass density of neutral gas using a fully automatic search for Damped Lyman-alpha systems in the Sloan Digital Sky Survey II Data Release 7.
415. Double-peaked AGN. I. Dual AGN candidates
ID:
ivo://CDS.VizieR/J/ApJ/753/42
Title:
Double-peaked AGN. I. Dual AGN candidates
Short Name:
J/ApJ/753/42
Date:
21 Oct 2021
Publisher:
CDS
Description:
Merger-remnant galaxies with kiloparsec (kpc) scale separation dual active galactic nuclei (AGNs) should be widespread as a consequence of galaxy mergers and triggered gas accretion onto supermassive black holes, yet very few dual AGNs have been observed. Galaxies with double-peaked narrow AGN emission lines in the Sloan Digital Sky Survey (SDSS) are plausible dual AGN candidates, but their double-peaked profiles could also be the result of gas kinematics or AGN-driven outflows and jets on small or large scales. To help distinguish between these scenarios, we have obtained spatial profiles of the AGN emission via follow-up long-slit spectroscopy of 81 double-peaked narrow-line AGNs in SDSS at 0.03<=z<=0.36 using Lick, Palomar, and MMT Observatories. We find that all 81 systems exhibit double AGN emission components with ~kpc projected spatial separations on the sky (0.2h^-1^_70_kpc<{Delta}x<5.5h^-1^_70_kpc; median {Delta}x=1.1h^-1^_70_kpc), which suggests that they are produced by kiloparsec-scale dual AGNs or kiloparsec-scale outflows, jets, or rotating gaseous disks.
416. Double-peaked narrow lines in AGN. II. z<0.1
ID:
ivo://CDS.VizieR/J/ApJ/832/67
Title:
Double-peaked narrow lines in AGN. II. z<0.1
Short Name:
J/ApJ/832/67
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present optical long-slit observations of the complete sample of 71 Type 2 active galactic nuclei (AGNs) with double-peaked narrow emission lines at z<0.1 in the Sloan Digital Sky Survey. Double-peaked emission lines are produced by a variety of mechanisms including disk rotation, kiloparsec-scale dual AGNs, and narrow-line region (NLR) kinematics (outflows or inflows). We develop a novel kinematic classification technique to determine the nature of these objects using long-slit spectroscopy alone. We determine that 86% of the double-peaked profiles are produced by moderate-luminosity AGN outflows, 6% are produced by rotation, and 8% are ambiguous. While we are unable to directly identify dual AGNs with long-slit data alone, we explore their potential kinematic classifications with this method. We also find a positive correlation between the NLR size and luminosity of the AGN NLRs (R_NLR_{propto}L_[OIII]_^0.21+/-0.05^), indicating a clumpy two-zone ionization model for the NLR.
417. Double-peaked narrow lines in AGN. IV. Mergers
ID:
ivo://CDS.VizieR/J/ApJ/867/66
Title:
Double-peaked narrow lines in AGN. IV. Mergers
Short Name:
J/ApJ/867/66
Date:
21 Oct 2021
Publisher:
CDS
Description:
Double-peaked narrow emission lines in active galactic nucleus (AGN) spectra can be produced by AGN outflows, rotation, or dual AGNs, which are AGN pairs in ongoing galaxy mergers. Consequently, double-peaked narrow AGN emission lines are useful tracers of the coevolution of galaxies and their supermassive black holes, as driven by AGN feedback and AGN fueling. We investigate this concept further with follow-up optical longslit observations of a sample of 95 Sloan Digital Sky Survey (SDSS) galaxies that have double-peaked narrow AGN emission lines. Based on a kinematic analysis of the longslit spectra, we confirm previous work that finds that the majority of double-peaked narrow AGN emission lines are associated with outflows. We also find that eight of the galaxies have companion galaxies with line-of-sight velocity separations <500km/s and physical separations <30kpc. Since we find evidence of AGNs in both galaxies, all eight of these systems are compelling dual AGN candidates. Galaxies with double-peaked narrow AGN emission lines occur in such galaxy mergers at least twice as often as typical active galaxies. Finally, we conclude that at least 3% of SDSS galaxies with double-peaked narrow AGN emission lines are found in galaxy mergers where both galaxies are resolved in SDSS imaging.
418. DPOSS II compact group survey
ID:
ivo://CDS.VizieR/J/A+A/445/857
Title:
DPOSS II compact group survey
Short Name:
J/A+A/445/857
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents the results of a pilot redshift survey of 18 candidate compact groups from the distant DPOSS survey that extends to redshift 0.2 the available surveys of compact groups of galaxies, mainly Hickson Compact Groups and Southern Compact Groups. The goal of our survey was to confirm group membership via redshift information and to measure the characteristic parameters of a representative, albeit small, sample of DPOSS survey groups.
419. DPOSS II compact group survey. EMMI-NTT sample
ID:
ivo://CDS.VizieR/J/A+A/539/A106
Title:
DPOSS II compact group survey. EMMI-NTT sample
Short Name:
J/A+A/539/A106
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a redshift survey of 138 candidate compact groups from the DPOSS II catalogue, which extends the available redshift range of spectroscopically confirmed compact groups of galaxies to redshift z~0.2. In this survey, we aim to confirm group membership via spectroscopic redshift information, to measure the characteristic properties of the confirmed groups, namely their mass, radius, luminosity, velocity dispersion, and crossing time, and to compare them with those of nearby compact groups. Using information available from the literature, we also studied the surrounding group environment and searched for additional, previously unknown, group members, or larger scale structures to whom the group might be associated.
420. 3D spectroscopy in 30 Dor
ID:
ivo://CDS.VizieR/J/ApJS/191/160
Title:
3D spectroscopy in 30 Dor
Short Name:
J/ApJS/191/160
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have completed a new optical imaging and spectrophotometric survey of a 140x80pc^2^ region of 30 Doradus centered on R136, covering key optical diagnostic emission lines including H{alpha}, H{beta}, H{gamma}, [OIII]4363, 4959, 5007, [NII]6548, 6584, [SII]6717, 6731 [SIII]6312, and in some locations [SIII]9069. We present maps of fluxes and intensity ratios for these lines, and catalogs of isolated ionizing stars, elephant-trunk pillars, and edge-on ionization fronts. The final science-quality spectroscopic data products are available to the public. Our analysis of the new data finds that, while stellar winds and supernovae undoubtedly produce shocks and are responsible for shaping the nebula, there are no global spectral signatures to indicate that shocks are currently an important source of ionization. We conclude that the considerable region covered by our survey is well described by photoionization from the central cluster where the ionizing continuum is dominated by the most massive O stars. We show that if 30 Dor were viewed at a cosmological distance, its integrated light would be dominated by its extensive regions of lower surface brightness rather than by the bright, eye-catching arcs.