adsabs/SciX_UAT_keywords huggingface dataset:
Constraining Cosmological Parameters Using the Cluster Mass-Richness Relation

The cluster mass-richness relation (MRR) is an observationally efficient and potentially powerful cosmological tool for constraining the matter density Ωm and the amplitude of fluctuations σ 8 using the cluster abundance technique. We derive the MRR relation using GalWCat19, a publicly available galaxy cluster catalog we created from the Sloan Digital Sky Survey-DR13 spectroscopic data set. In the MRR, cluster mass scales with richness as $\mathrm{log}{M}_{200}=\alpha +\beta \mathrm{log}{N}_{200}$ . We find that the MRR we derive is consistent with both the IllustrisTNG and mini-Uchuu cosmological numerical simulations, with a slope of β ≈ 1. We use the MRR we derived to estimate cluster masses from the GalWCat19 catalog, which we then use to set constraints on Ωm and σ 8. Utilizing the all-member MRR, we obtain constraints of Ωm = ${0.31}_{-0.03}^{+0.04}$ and σ 8 = ${0.82}_{-0.04}^{+0.05}$ , and utilizing the red member MRR only, we obtain Ωm = ${0.31}_{-0.03}^{+0.04}$ and σ 8 = ${0.81}_{-0.04}^{+0.05}$ . Our constraints on Ωm and σ 8 are consistent and very competitive with the Planck 2018 results.

Keywords: galaxy clusters; cosmological parameters; galaxy cluster counts
Photometric BVR Observations of (65803) Didymos after DART

The near-Earth binary asteroid Didymos was observed by robotic telescopes in Australia, Chile, and the United States three to five weeks after its impact with the DART spacecraft. The B - R spectral slope of the Didymos system was 13% ± 1%/100 nm, redder than that of the Sun, active comets, and its previously measured colors. The dust cloud around the Didymos system caused a mean drop of 0.29 ± 0.08 mag and had an optical thickness of 0.27 ± 0.07, based on observations from October 27.743 and 28.740 UT. The mean FWHM of the photometric profile of the Didymos system was 1.1 ± 0.1 larger than that of the unsaturated field stars in the R band during our observing campaign. According to our results, the B - R color index was the best parameter to detect the activity of this asteroid in the visible range.

Keywords: near-earth objects; apollo group; asteroids; multi-color photometry
The Star-forming Main Sequence and the Contribution of Dust-obscured Star Formation since z ∼ 4 from the Far-UV+IR Luminosity Functions

An analytical approach is proposed to study the evolution of the star-forming galaxy (SFG) main sequence (MS) and the fraction of dust-obscured star formation (SF) up to z ∼ 4. Far-ultraviolet (FUV) and infrared (IR) star formation rates (SFRs) are described as conditional probability functions of M*. We convolve them with the galaxy stellar mass function (GSMF) of SFGs to derive the FUV and IR luminosity functions (LFs). The two SF modes formalism is used to describe starburst galaxies. By fitting observed FUV and IR LFs, the parameterization of SFRFUV-M* and SFRIR- M* is constrained. Our derived SFRFUV+IR-M* reproduces the evolution of the MS as compared to other observational inferences. At any redshift, we find that the sSFRFUV+IR-M* relation for MS SFGs approaches a power law at the high-mass end. At lower masses, it bends, and eventually, the slope sign changes from negative to positive at very low masses. At z ∼ 0, this change of sign is at M* ∼ 5 × 108 M⊙, close to the dust-obscured SF regime, M* ∼ 6 × 108 M⊙. The slope sign change is related to the knee of the FUV LF. Our derived dust-obscured fractions agree with previous determinations at 0 ≤ z ≤ 2.5. Dust-obscured fractions depend strongly on mass with almost no dependence on redshift at z ≳ 1.2. At z ≲ 0.75, high-mass galaxies become more "transparent" compared to their high-redshift counterparts. On the other hand, low- and intermediate-mass galaxies have become more obscured by dust. The joint evolution of the GSMF and the FUV and IR LFs is a promising approach to study mass growth and dust formation/destruction mechanisms.

Keywords: galaxy abundances; galaxy counts; galaxy evolution; galaxy processes
Kinematic-chemical Analysis and Time Tagging for the Diagonal Ridge Structure of the Galactic Outer Disk with LAMOST Red-giant Branch Stars

We investigate the kinematic-chemical distribution of red-giant branch stars from the LAMOST survey crossed matched with Gaia DR2 proper motions, and present time tagging for the well-known ridge structures (diagonal distributions for V R in the R, V ϕ plane) in the range of Galactocentric distance R = 8 to 15 kpc. We detect six ridge structures, including five ridges apparent in the radial velocity distribution and three ridges apparent in the vertical velocity, the sensitive time of which to the perturbations are from young population (0-3 Gyr) to old population (9-14 Gyr). Based on an analysis of the evolution of angular momentum distribution, we find that four ridges are relatively stationary, while another is evolving with time, which is confirmed by the difference analysis at different populations and supporting that there might be two kinds of dynamical origins. Furthermore, ridge features are also vividly present in the chemical properties ([Fe/H], [α/Fe]). The comparison between the north and south hemispheres of the Galaxy does show some differences and the ridge features are asymmetrical. Moreover, we find that diagonal ridge structures may affect the shape of the rotation curve, which is manifested as fluctuations and undulations on top of a smooth profile. Finally we speculate that the bar dynamics should be not enough to explain all ridge properties including the break feature in the V Z -L Z plane.

Keywords: milky way disk; milky way formation
Catalog of Planetary Nebulae Detected by GALEX and Corollary Optical Surveys

Planetary nebulae (PNs) consist of an ionized envelope surrounding a hot central star (CSPN) that emits mostly at ultraviolet (UV) wavelengths. UV observations, therefore, provide important information on both the CSPN and the nebula. We have matched the PNs in the Hong Kong/Australian Astronomical Observatory/Strasbourg Hα catalog with the Galaxy Evolution Explorer (GALEX) UV sky surveys, the Sloan Digital Sky Survey (SDSS) data release 16, and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) PS1 second release. A total of 671 PNs were observed by GALEX with the far-UV (FUV; 1344 Å-1786 Å) and/or the near-UV (NUV; 1771 Å-2831 Å) detectors on (GUVPNcat); 83 were observed by SDSS (PNcatxSDSSDR16) and 1819 by Pan-STARRS (PNcatxPS1MDS). We merged a distilled version of these matched catalogs into GUVPNcatxSDSSDR16xPS1MDS, which contains a total of 375 PNs with both UV and optical photometry over a total spectral coverage of ~1540 Å-9610 Å. We analyzed separately 170 PNs resolved in GALEX images and determined their UV radius by applying a flux profile analysis. The CSPN flux could be extracted separately from the PN emission for 8 and 50 objects with SDSS and Pan-STARRS counterparts, respectively. The multiband photometry was used to distinguish between compact and extended PNs and CSPNs (binary CSPNs) by color-color diagram analysis. We found that compact PN candidates could be identified by using the r - i < - 0.4 and -1 < FUV-NUV < 1 colors, whereas binary CSPN candidates in given T eff ranges (all with color r-i > -0.4) can be identified in the color region (FUV-NUV) ≤ 6(r-i)+1.3, -0.8 < FUV-NUV < 0.4, and r-i < 0.75.

Keywords: astronomy databases; planetary nebulae; planetary nebulae nuclei; white dwarf stars; ultraviolet astronomy; emission nebulae; catalogs; sky surveys
Role of Magnetic Fields in the Formation of Direct Collapse Black Holes

Direct collapse black holes are the leading candidates for the origin of the first supermassive black holes. However, the role of magnetic fields during their formation is still unclear as none of the previous studies has been evolved long enough to assess their impact during the accretion phase. Here, we report the results from a suite of 3D cosmological magnetohydrodynamic (MHD) simulations which are evolved for 1.6 Myr comparable to the expected lifetime of supermassive stars (SMSs). Our findings suggest that magnetic fields are rapidly amplified by strong accretion shocks irrespective of the initial magnetic field strength and reach the saturation state. They stabilize the accretion disks and significantly reduce fragmentation by enhancing the Jeans mass in comparison with pure hydrodynamical runs. Although the initial clump masses are larger in MHD runs, the rapid coalescence of clumps in non-MHD cases due to the higher degree of fragmentation results in similar masses. Overall, the central clumps have masses of 105 M ⊙ and the mean mass accretion rates of ~0.1 M ⊙ yr-1 are similar in both MHD and non-MHD cases. The multiplicity of SMSs is significantly reduced in MHD simulations. Such strongly amplified magnetic fields are expected to launch jets and outflows which may be detected with upcoming radio telescopes.

Keywords: population iii stars; early universe; supermassive black holes; computational methods; primordial galaxies
Revisiting the Complex Kinematics of Ionized Gas at the Central Region of NGC 1068: Evidence of an Additional Active Galactic Nucleus?

We present a spatially resolved analysis of ionized gas at the nuclear region of the nearby galaxy NGC 1068. While NGC 1068 has been known to have gas outflows driven by its active galactic nucleus (AGN), more complex kinematical signatures were recently reported, which were inconsistent with rotation or simple biconical outflows. To account for the nature of gas kinematics, we performed a spatially resolved kinematical study, finding a morphologically symmetric pair of approaching and receding gas blobs in the northeast region. The midpoint of the two blobs is located at a distance of 180 pc from the nucleus in the projected plane. The ionized gas at the midpoint shows zero velocity and high velocity dispersion, which are characteristics of an outflow-launching position, as the two sides of a bicone, i.e., approaching and receding outflows are superposed on the line of sight, leading to no velocity shift but high velocity dispersion. We investigate the potential scenario of an additional AGN based on a multiwavelength data set. While there are other possibilities, i.e., X-ray binary or supernova shock, the results from optical spectropolarimetry analysis are consistent with the presence of an additional AGN, which likely originates from a minor merger.

Keywords: active galactic nuclei; spectroscopy
Col-OSSOS: The Two Types of Kuiper Belt Surfaces

The Colors of the Outer Solar System Origins Survey (Col-OSSOS) has gathered a high-quality, near-simultaneous, and brightness-complete sample of (g - r) and (r - J) colors for 102 Kuiper Belt objects (KBOs) with (u - g) and (r - z) gathered for some. We present the current state of the survey and data analysis. Recognizing that the optical colors of most icy bodies broadly follow the reddening curve, we present a new projection of the optical-near-IR (NIR) colors, which rectifies the main nonlinear features in the optical-NIR along the ordinates. We find evidence for a bifurcation in the projected colors that presents itself as a diagonal empty region in the optical-NIR. A reanalysis of past color surveys reveals the same bifurcation. We interpret this as evidence for two separate surface classes: the BrightIR class spans the full range of optical colors and broadly follows the reddening curve, while the FaintIR objects are limited in optical color and are less bright in the NIR than the BrightIR objects. We present a two-class model. Objects in each class consist of a mix of separate blue and red materials and span a broad range in color. Spectra are modeled as linear optical and NIR spectra with different slopes that intersect at some transition wavelength. The underlying spectral properties of the two classes reproduce the main observed structures in the UV-optical-NIR color space (0.4 μm ≲ λ ≲ 1.4 μm), including the bifurcation observed in the Col-OSSOS and H/WTSOSS data sets, including the tendency for cold classical KBOs to have lower (r - z) colors than excited objects, and the well-known bimodal optical color distribution.

Keywords: kuiper belt; photometry; surface composition; planetesimals; trans-neptunian objects
Oblique Compressible Waves in the Reconnection Exhaust Region Embedded in the Inner Heliospheric Current Sheet Observed by Parker Solar Probe

Magnetic reconnection is an important physical process of energy conversion in the heliosphere. Parker Solar Probe (PSP) passes through current sheets of the inner heliosphere and is likely to encounter magnetic reconnection events there. PSP traversed a magnetic reconnection exhaust region that occurred in the coronal streamer during its perihelion Encounter 8. We report an observation of the counterstream of strahl electrons and compressible waves in the exhaust region on the antisunward side of the reconnection site. We analyze the wave characteristics using electromagnetic singular value decomposition techniques and find that the propagation direction of the compressible waves is quasi-perpendicular to the local magnetic field. Combining with the topology of the magnetic field, we infer that the compressible waves converge from the edge to the center of the exhaust region, and then propagate away from it. Further, we select 12 magnetic reconnection events during Encounter 5–8 for statistics and find that the oblique compressible waves are commonly detected throughout the inner heliospheric current sheet. In addition, we discuss the possible nature of wave branches for these compressible waves. Our work shows that magnetic reconnection in the heliosphere not only changes the topology of the large-scale magnetic field in the heliosphere, but also affects the transport characteristics of solar wind plasma and suprathermal particles, and regulates the states of waves and turbulence in the heliosphere.

Keywords: solar wind; solar magnetic reconnection; alfven waves; heliosphere
A Radio Quasi-periodic Oscillation of 176 days in the Radio-loud Narrow-line Seyfert 1 Galaxy J0849+5108

We analyze the 11 yr long-term light curve of the Radio-loud Narrow-line Seyfert 1 galaxy J0849+5108 and the nearly simultaneous γ-ray data of the source. The data were obtained with the Owens Valley Radio Observatory 40 m telescope at 15 GHz and with the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope, respectively. A quasi-periodic oscillation (QPO) signal at a significance of >5σ is found in the radio light curve, but no similar modulation is seen in the γ-ray light curve. The QPO signal was present for 21 cycles, the longest among the reported radio QPOs, and likely disappeared after 2019 January 16. Different mechanisms proposed to explain the observed QPOs in active galactic nuclei (AGNs) are discussed for this QPO case. Either a secular instability in the inner accretion disk or a helical structure in the jet of J0849+5108 may explain the radio QPO, while for the latter scenario the jet has to be collimated up to ~200 pc, similar to that seen in the nearby AGN M87. It will be of interest to keep monitoring the source at radio frequencies, seeing whether similar QPO signals appear again.

Keywords: radio jets; active galactic nuclei; periodic orbit
Deciphering the Origin of the GeV-TeV Gamma-Ray Emission from SS 433

We investigate hadronic and leptonic scenarios for the GeV-TeV gamma-ray emission from jets of the microquasar SS 433. The emission region of the TeV photons coincides with the X-ray knots, where electrons are efficiently accelerated. On the other hand, the optical high-density filaments are also located close to the X-ray knots, which may support a hadronic scenario. We calculate multiwavelength photon spectra of the extended jet region by solving the transport equations for the electrons and protons. We find that both hadronic and leptonic models can account for the observational data, including the latest Fermi Large Area Telescope result. The hadronic scenarios predict higher-energy photons than the leptonic scenarios, and future observations such as with the Cherenkov Telescope Array, the Large High-Altitude Air Shower Observatory, and the Southern Wide-field Gamma-ray Observatory may distinguish between these scenarios and unravel the emission mechanism of GeV-TeV gamma rays. Based on our hadronic scenario, the analogy between microquasars and radio galaxies implies that the X-ray knot region of the radio-galaxy jets may accelerate heavy nuclei up to ultrahigh energies.

Keywords: gamma-ray astronomy; jets; non-thermal radiation sources; cosmic ray sources
Research on Multiwavelength Isolated Bright Points Based on Deep Learning

Multiwavelength bright points (BPs) are taken to be cross sections of magnetic flux tubes extending from the surface of the photosphere upward to the higher photosphere. We aim to study the characteristics of isolated multiwavelength BPs using the cotemporal and cospatial TiO band and Hα line wings from the Goode Solar Telescope at Big Bear Solar Observatory. A deep-learning method, based on Track Region-based Convolutional Neural Networks, is proposed to detect, segment, and match the BPs across multiple wavelength observations, including the TiO, Hα + 1 Å, Hα - 1 Å, Hα + 0.8 Å, and Hα - 0.8 Å line wings. Based on the efficient detection and matching result with a precision of 0.98, 1283 groups of BPs matched in all five wavelengths are selected for statistics analysis. The characteristic values of the BPs observed at the same red and blue line wings are averaged. For the BPs of the TiO, averaged Hα ± 1 Å, and averaged Hα ± 0.8 Å line wings, the mean equivalent diameters are 162 ± 32, 254 ± 33, and 284 ± 28 km, respectively. The maximum intensity contrasts are 1.11 ± 0.09, 1.05 ± 0.03, and 1.05 ± 0.02 $\left\langle {I}_{\mathrm{QS}}\right\rangle $ , respectively. The mean eccentricities are 0.65 ± 0.14, 0.63 ± 0.11, and 0.65 ± 0.11, respectively. Moreover, the characteristic ratios of each Hα ± 1 Å and Hα ± 0.8 Å BP to its corresponding TiO BP are derived. Hα ± 1 Å and Hα ± 0.8 Å line wings BPs show 60% and 80% increases compared to TiO BPs, respectively. With increasing height, most BPs almost keep their shapes. This work is helpful for modeling the three-dimensional structure of flux tubes.

Keywords: quiet sun; solar photosphere; astronomical methods; convolutional neural networks
Post-starburst Galaxies in SDSS-IV MaNGA: Two Broad Categories of Evolutionary Pathways

We study the size–mass relation (SMR) and recent star formation history (SFH) of post-starburst (PSB) galaxies in the local Universe using spatially resolved spectroscopy from the final data release of MaNGA. Our sample includes 489 PSB galaxies: 94 cPSB galaxies with central PSB regions, 85 rPSB galaxies with ringlike PSB regions, and 310 iPSB galaxies with irregular PSB regions. When compared to control galaxies of similar star formation rate, redshift, and mass, a similar SMR is found for all types of PSB samples except the cPSB galaxies, which have smaller sizes at intermediate masses ( $9.5\lesssim {\mathrm{log}}_{10}({M}_{* }/{M}_{\odot })\lesssim 10.5$ ). The iPSB galaxies in the star-forming sequence (iPSB-SF) show no/weak gradients in D n (4000), EW(Hδ A ), and EW(Hα), consistent with the global star-forming status of this type of galaxy, while the quiescent iPSB (iPSB-Q) sample shows negative gradients in D n (4000) and positive gradients in EW(Hδ A ), indicating older stellar populations in the inner regions. Both the cPSB and rPSB samples show positive gradients in D n (4000) and negative gradients in EW(Hδ A ), indicating younger stellar populations in the inner regions. These results imply that the four types of PSB galaxies can be broadly divided into two distinct categories in terms of evolutionary pathway: (1) iPSB-SF and iPSB-Q, which have SMRs and SFHs similar to control galaxies, preferring an inside-out quenching process, and (2) rPSB and cPSB, which appear to be different stages of the same event and likely to follow the outside-in quenching process driven by disruption events such as mergers that result in a more compact structure as quenching proceeds.

Keywords: post-starburst galaxies; galaxy evolution
MMS Observations of Energized He+ Pickup Ions at Quasiperpendicular Shocks

Accelerated He+ pickup ions (PUIs) downstream of quasiperpendicular shocks are studied as a function of the fast-mode Mach number (Mf) and shock obliquity (θBn). We analyze 10 quasiperpendicular shocks with Mach numbers in the range [1, 7] observed by the Magnetospheric MultiScale (MMS) mission, and compare upstream and downstream He+ velocity distribution functions. For each shock event, we characterize the upstream PUI distribution and derive reduced 1D velocity distributions for the selected upstream and downstream intervals. We also compare the upstream-to-downstream ratio of spectral indices, computed from the He+ perpendicular distributions, to Mf and θBn. We find a positive correlation of this spectral index ratio and Mf, which suggests that perpendicular energization of He+ PUIs is enhanced as the shock becomes stronger. These results inform modeling efforts of PUIs and shock-acceleration processes, particularly those taking place at the termination shock.

Keywords: planetary bow shocks; pickup ions; termination shock; solar wind; shocks
Spectrotemporal Analysis of a Sample of Bursts from FRB 121102

FRB 121102 was the first Fast Radio Burst (FRB) that was shown to repeat. Since its discovery in 2012, more than two hundred bursts have been detected from the source. These bursts exhibit a diverse range of spectral and temporal characteristics and many questions about their origin and form remain unanswered. Here, we present a sample of radio bursts from FRB 121102 detected using the Lovell telescope at Jodrell Bank Observatory. We show four examples of bursts that show peculiar spectro-temporal characteristics and compare them with properties of bursts of FRB 121102 detected at other observatories. We report on a precursor burst that is separated by just 17 ms from the main burst, the shortest reported separation between two individual bursts to date. We also provide access to data for all the detections of FRB 121102 in this campaign.

Keywords: radio bursts; radio transient sources
Turbulence in the Local Interstellar Medium and the IBEX Ribbon

The effects of turbulence in the very local interstellar medium (VLISM) have been proposed by Giacalone & Jokipii to be important in determining the structure of the Interstellar Boundary Explorer (IBEX) ribbon via particle trapping by magnetic mirroring. We further explore this effect by simulating the motion of charged particles in a turbulent magnetic field superposed on a large-scale mean field, which we consider to be either spatially uniform or a draped field derived from a three-dimensional magnetohydrodynamic simulation. We find that the ribbon is not double-peaked, in contrast to Giacalone & Jokipii. However, the magnetic mirror force still plays an important role in trapping particles. Furthermore, the ribbon is considerably thicker if the large-scale mean field is draped around the heliosphere. Voyager 1 observations in the VLISM show a turbulent field component that is stronger than previously thought, which we test in our simulation. We find that the inclusion of turbulent fluctuations at scales ≳100 au and power consistent with Voyager 1 observations produces a ribbon whose large-scale structure is inconsistent with IBEX observations. However, restricting fluctuations to <100 au produces a smoother ribbon structure similar to IBEX observations. Different realizations of turbulence produce different small-scale features (≲10°) in the ribbon, but its large-scale structure is robust if the maximum fluctuation size is ≲50 au. This suggests that the magnetic field structure at scales ≲50 au is determined by the heliosphere-VLISM interaction and cannot entirely be represented by pristine interstellar turbulence.

Keywords: heliosphere; pickup ions; solar wind; interstellar medium; interstellar magnetic fields; particle physics; interplanetary turbulence