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- ID:
- ivo://pds-ppi/galileo_hic_jup_calibrated_highres_ganymede/ppi/epn_core
- Title:
- Galilieo Jupiter HIC Highres Energetic Ion Count Rate Ganymede Data Collection
- Short Name:
- HIG-J-HI-GAN
- Date:
- 15 Dec 2022 19:24:13
- Publisher:
- Planetary Data System
- Description:
- This collection contains Galileo HIC high resolution (LPW) pulse height data acquired at Jupiter and Ganymede.
- ID:
- ivo://pds-ppi/galileo_hic_jup_calibrated_highres_io/ppi/epn_core
- Title:
- Galilieo Jupiter HIC Highres Energetic Ion Count Rate IO Data Collection
- Short Name:
- HIG-J-HI-IO
- Date:
- 15 Dec 2022 19:27:01
- Publisher:
- Planetary Data System
- Description:
- This collection contains Galileo HIC high resolution (LPW) pulse height data acquired at Jupiter, Io, and in the Io plasma torus.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A89
- Title:
- G328.2551-0.5321 ALMA images
- Short Name:
- J/A+A/617/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The conditions leading to the formation of the most massive O-type stars, are still an enigma in modern astrophysics. To assess the physical conditions of high-mass protostars in their main accretion phase, here we present a case study of a young massive clump selected from the ATLASGAL survey, G328.2551-0.5321. The source exhibits a bolometric luminosity of 1.3x10^4^L_{sun}_, which allows us to estimate its current protostellar mass to be between ~11 and 16 M_{sun}_. We show high angular-resolution observations with ALMA reaching a physical scale of ~400au. To reveal the structure of this high-mass protostellar envelope in detail at a ~0.17" resolution, we use the thermal dust continuum emission and spectroscopic information, amongst others from the CO (J=3-2) line, which is sensitive to the high velocity molecular outflow, the SiO (J=8-7), and SO_2_ (J=8_2,6_-7_1,7_) lines tracing shocks along the outflow, as well as several CH_3_OH and HC_3_N lines that probe the gas of the inner envelope in the closest vicinity of the protostar. The dust continuum emission reveals a single high-mass protostellar envelope, down to our resolution limit. We find evidence for a compact, marginally resolved continuum source, which is surrounded by azimuthal elongations that could be consistent with a spiral pattern. We also report on the detection of a rotational line of CH_3_OH within its vt=1 torsionally excited state. This shows two bright peaks of emission spatially offset from the dust continuum peak, and exhibiting a distinct velocity component +/-4.5km/s offset compared to the source Vlsr. Rotational diagram analysis and models based on local thermodynamic equilibrium (LTE) assumption require high CH3OH column densities reaching N(CH_3_OH)=1.2-2x10^19^cm^-2^, and kinetic temperatures of the order of 160-200K at the position of these peaks. A comparison of their morphology and kinematics with those of the outflow component of the CO line, and the SO2 line suggests that the high excitation CH3OH spots are associated with the innermost regions of the envelope. While the HC_3_N v7=0 (J=37-36) line is also detected in the outflow, the HC_3_N v7=1e (J=38-37) rotational transition within the molecule's vibrationally excited state shows a compact morphology. We find that the velocity shifts at the position of the observed high excitation CH3OH spots correspond well to the expected Keplerian velocity around a central object with 15M_{sun}_ consistent with the mass estimate based on the source's bolometric luminosity. We propose a picture where the CH_3_OH emission peaks trace the accretion shocks around the centrifugal barrier, pinpointing the interaction region between the collapsing envelope and an accretion disk. The physical properties of the accretion disk inferred from these observations suggest a specific angular momentum several times larger than typically observed towards low-mass protostars. This is consistent with a scenario of global collapse setting on at larger scales that could carry a more significant amount of kinetic energy compared to the core collapse models of low-mass star formation. Furthermore, our results suggest that vibrationally exited HC_3_N emission could be a new tracer for compact accretion disks around high-mass protostars.
- ID:
- ivo://CDS.VizieR/J/A+A/621/A122
- Title:
- G351.77-0.54 ALMA observations
- Short Name:
- J/A+A/621/A122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The hierarchical process of star formation has so far mostly been studied on scales from thousands of au to parsecs, but the smaller sub-1000 au scales of high-mass star formation are still largely unexplored in the submm regime. We aim to resolve the dust and gas emission at the highest spatial resolution to study the physical properties of the densest structures during high-mass star formation. We observed the high-mass hot core region G351.77-0.54 with the Atacama Large Millimeter Array with baselines extending out to more than 16 km. This allowed us to dissect the region at sub-50 au spatial scales. At a spatial resolution of 18/40au (depending on the distance), we identify twelve sub-structures within the inner few thousand au of the region. The brightness temperatures are high, reaching values greater 1000K, signposting high optical depth toward the peak positions. Core separations vary between sub-100 au to several 100 and 1000au. The core separations and approximate masses are largely consistent with thermal Jeans fragmentation of a dense gas core. Due to the high continuum optical depth, most spectral lines are seen in absorption. However, a few exceptional emission lines are found that most likely stem from transitions with excitation conditions above 1000K. Toward the main continuum source, these emission lines exhibit a velocity gradient across scales of 100-200au aligned with the molecular outflow and perpendicular to the previously inferred disk orientation.While we cannot exclude that these observational features stem from an inner hot accretion disk, the alignment with the outflow rather suggests that it stems from the inner jet and outflow region. The highest-velocity features are found toward the peak position, and no Hubble-like velocity structure can be identified. Therefore, these data are consistent with steady-state turbulent entrainment of the hot molecular gas via Kelvin-Helmholtz instabilities at the interface between the jet and the outflow. Resolving this high-mass star-forming region at sub-50au scales indicates that the hierarchical fragmentation process in the framework of thermal Jeans fragmentation can continue down to the smallest accessible spatial scales. Velocity gradients on these small scales have to be treated cautiously and do not necessarily stem from disks, but may be better explained with outflow emission. Studying these small scales is very powerful, but covering all spatial scales and deriving a global picture from large to small scales are the next steps to investigate.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A113
- Title:
- GalMer S0 remnants morphological properties
- Short Name:
- J/A+A/617/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Major mergers are popularly considered too destructive to produce the relaxed regular structures and the morphological inner components (ICs) usually observed in lenticular (S0) galaxies. We have tested if major mergers can produce remnants with realistic S0 morphologies. We have selected a sample of relaxed discy remnants resulting from the dissipative merger simulations of the GalMer database and derived their morphological properties mimicking the typical conditions of current observational data. Only ~1-2Gyr after the full merger, we find that: 1) many remnants (67 major and 29 minor events) present relaxed structures and typical S0 or E/S0 morphologies, for a wide variety of orbits and even in gas-poor cases. 2) Most of them do not exhibit any morphological traces of their past merger origin under typical observing conditions and at distances as nearby as 30Mpc. 3) The merger relics are more persistent in minor mergers than in major ones for similar relaxing time periods. 4) No major-merger S0-like remnant develops a significant bar. 5) Nearly 58% of the major-merger S0 remnants host visually detectable ICs, such as embedded inner discs, rings, pseudo-rings, inner spirals, nuclear bars, and compact sources, very frequent in real S0s too. 6) All remnants contain a lens or oval, identically ubiquitous in local S0s. 7) These lenses and ovals do not come from bar dilution in major-merger cases, but are associated with stellar halos or embedded inner discs instead (thick or thin). We conclude that the relaxed morphologies, lenses, ovals, and other ICs of real S0s do not necessarily come from internal secular evolution, gas infall, or environmental mechanisms, as traditionally assumed, but they can result from major mergers as well.
- ID:
- ivo://CDS.VizieR/J/ApJS/254/33
- Title:
- Gal. midplane Spitzer/IRAC candidate YSOs (SPICY)
- Short Name:
- J/ApJS/254/33
- Date:
- 19 Jan 2022 09:09:49
- Publisher:
- CDS
- Description:
- We present ~120000 Spitzer/IRAC candidate young stellar objects (YSOs) based on surveys of the Galactic midplane between l~255{deg} and 110{deg}, including the GLIMPSE I, II, and 3D, Vela-Carina, Cygnus X, and SMOG surveys (613 square degrees), augmented by near-infrared catalogs. We employed a classification scheme that uses the flexibility of a tailored statistical learning method and curated YSO data sets to take full advantage of Spitzer's spatial resolution and sensitivity in the mid-infrared ~3-9{mu}m range. Multiwavelength color/magnitude distributions provide intuition about how the classifier separates YSOs from other red IRAC sources and validate that the sample is consistent with expectations for disk/envelope-bearing pre-main-sequence stars. We also identify areas of IRAC color space associated with objects with strong silicate absorption or polycyclic aromatic hydrocarbon emission. Spatial distributions and variability properties help corroborate the youthful nature of our sample. Most of the candidates are in regions with mid-IR nebulosity, associated with star-forming clouds, but others appear distributed in the field. Using Gaia DR2 distance estimates, we find groups of YSO candidates associated with the Local Arm, the Sagittarius-Carina Arm, and the Scutum-Centaurus Arm. Candidate YSOs visible to the Zwicky Transient Facility tend to exhibit higher variability amplitudes than randomly selected field stars of the same magnitude, with many high-amplitude variables having light-curve morphologies characteristic of YSOs. Given that no current or planned instruments will significantly exceed IRAC's spatial resolution while possessing its wide-area mapping capabilities, Spitzer-based catalogs such as ours will remain the main resources for mid-infrared YSOs in the Galactic midplane for the near future.
7028. GALPROP programme
- ID:
- ivo://CDS.VizieR/J/A+A/534/A54
- Title:
- GALPROP programme
- Short Name:
- J/A+A/534/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We exploit synchrotron radiation to constrain the low-energy interstellar electron spectrum, using various radio surveys and connecting with electron data from Fermi-LAT and other experiments. The GALPROP programme for cosmic-ray propagation, gamma-ray and synchrotron radiation is used. Secondary electrons and positrons are included. Propagation models based on cosmic-ray and gamma-ray data are tested against synchrotron data from 22MHz to 94GHz.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/11
- Title:
- Gal. redshift survey near HST/COS AGN sight lines
- Short Name:
- J/ApJS/237/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To establish the connection between galaxies and UV-detected absorption systems in the local universe, a deep (g<=20) and wide (~20' radius) galaxy redshift survey is presented around 47 sight lines to UV-bright AGNs observed by the Cosmic Origins Spectrograph (COS). Specific COS science team papers have used this survey to connect absorbers to galaxies, groups of galaxies, and large-scale structures, including voids. Here we present the technical details of the survey and the basic measurements required for its use, including redshifts for individual galaxies and uncertainties determined collectively by spectral class (emission-line, absorption-line, and composite spectra) and completeness for each sight line as a function of impact parameter and magnitude. For most of these sight lines, the design criteria of >90% completeness over a >1Mpc region down to <~0.1L* luminosities at z<=0.1 allows a plausible association between low-z absorbers and individual galaxies. Ly{alpha} covering fractions are computed to approximate the star-forming and passive galaxy populations using the spectral classes above. In agreement with previous results, the covering fraction of star-forming galaxies with L>=0.3L* is consistent with unity inside one virial radius and declines slowly to >50% at four virial radii. On the other hand, passive galaxies have lower covering fractions (~60%) and a shallower decline with impact parameter, suggesting that their gaseous halos are patchy but have a larger scale-length than star-forming galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/4277
- Title:
- GAMA blended spectra catalogue
- Short Name:
- J/MNRAS/449/4277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of blended galaxy spectra from the Galaxy And Mass Assembly (GAMA) survey. These are cases where light from two galaxies are significantly detected in a single GAMA fibre. Galaxy pairs identified from their blended spectrum fall into two principal classes: they are either strong lenses, a passive galaxy lensing an emission-line galaxy; or occulting galaxies, serendipitous overlaps of two galaxies, of any type. Blended spectra can thus be used to reliably identify strong lenses for follow-up observations (high-resolution imaging) and occulting pairs, especially those that are a late-type partly obscuring an early-type galaxy which are of interest for the study of dust content of spiral and irregular galaxies. The GAMA survey setup and its AUTOZ automated redshift determination were used to identify candidate blended galaxy spectra from the cross-correlation peaks. We identify 280 blended spectra with a minimum velocity separation of 600km/s, of which 104 are lens pair candidates, 71 emission-line-passive pairs, 78 are pairs of emission-line galaxies and 27 are pairs of galaxies with passive spectra. We have visually inspected the candidates in the Sloan Digital Sky Survey (SDSS) and Kilo Degree Survey (KiDS) images. Many blended objects are ellipticals with blue fuzz (Ef in our classification). These latter 'Ef' classifications are candidates for possible strong lenses, massive ellipticals with an emission-line galaxy in one or more lensed images. The GAMA lens and occulting galaxy candidate samples are similar in size to those identified in the entire SDSS. This blended spectrum sample stands as a testament of the power of this highly complete, second-largest spectroscopic survey in existence and offers the possibility to expand e.g. strong gravitational lens surveys.