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- ID:
- ivo://CDS.VizieR/J/A+A/559/A10
- Title:
- Arp 102B spectral optical monitoring
- Short Name:
- J/A+A/559/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of long-term (1987-2010) optical spectral monitoring of the broad-line radio galaxy Arp 102B, a prototype of an active galactic nucleus with double-peaked broad emission lines that are commonly assumed to be emitted from an accretion disk. To explore the structure of the broad-line region (BLR), we analyze the light-curves of the broad H{alpha} and H{beta} lines and the continuum flux. We aim to estimate the dimensions of the broad-line emitting regions and the mass of the central black hole. We used the cross correlation function to find lags between the lines and continuum variations. We investigated the correlation between line and continuum fluxes in more detail, and explored periodical variations of the red-to-blue line flux ratio using Lomb-Scargle periodograms.
- ID:
- ivo://CDS.VizieR/J/A+A/621/A25
- Title:
- Arp 240 Fabry-Perot interferometry
- Short Name:
- J/A+A/621/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Encounters between galaxies modify their morphology, kinematics, and star formation history. The relation between these changes and external perturbations is not straightforward. The great number of parameters involved requires both the study of large samples and individual encounters where particular features, motions, and perturbations can be traced and analysed in detail. We analysed the morphology, kinematics, and dynamics of two luminous infrared spiral galaxies of almost equal mass, NGC 5257 and NGC 5258, in which star formation is mostly confined to the spiral arms, in order to understand interactions between galaxies of equivalent masses and star-forming processes during the encounter. Using scanning Fabry-Perot interferometry, we studied the contribution of circular and non-circular motions and the response of the ionized gas to external perturbations. We compared the kinematics with direct images of the pair and traced the star-forming processes and gravitational effects due to the presence of the other galaxy. The spectral energy distribution of each member of the pair was fitted. A mass model was fitted to the rotation curve of each galaxy. Large, non-circular motions detected in both galaxies are associated with a bar, spiral arms, and HII regions for the inner parts of the galaxies, and with the tidal interaction for the outer parts of the discs. Bifurcations in the rotation curves indicate that the galaxies have recently undergone their pericentric passage. The pattern speed of a perturbation of one of the galaxies is computed. Location of a possible corotation seems to indicate that the gravitational response of the ionized gas in the outer parts of the disc is related to the regions where ongoing star formation is confined. The spectral energy distribution (SED) fit indicates a slightly different star formation history for each member of the pair. For both galaxies, a pseudo-isothermal halo better fits the global mass distribution.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A25
- Title:
- Arp 220 HCN and HCO^+^ data cubes
- Short Name:
- J/A+A/590/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The origin of the enormous luminosities of the two opaque nuclei of Arp 220, the prototypical ultra-luminous infrared galaxy, remains a mystery because we lack observational tools to explore the innermost regions around the nuclei. We explore the potential of imaging vibrationally excited molecular emission at high angular resolution to better understand the morphology and physical structure of the dense gas in Arp 220 and to gain insight into the nature of the nuclear powering sources. The Atacama Large Millimeter/submillimeter Array (ALMA) provided simultaneous observations of HCN, HCO^+^, and vibrationally excited HCN v_2_=1f emission. Their J=4-3 and 3-2 transitions were observed at a matching resolution of ~0.5", which allows us to isolate the emission from the two nuclei.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A86
- Title:
- Arp 220 LOFAR radio images at 150MHz
- Short Name:
- J/A+A/593/A86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse new observations with the International Low Frequency Array (LOFAR) telescope, and archival data from the Multi-Element Radio Linked Interferometer Network (MERLIN) and the Karl G. Jansky Very Large Array (VLA). We model the spatially resolved radio spectrum of Arp 220 from 150MHz to 33GHz. We present an image of Arp 220 at 150MHz with resolution 0.65"x0.35", sensitivity 0.15mJy/beam, and integrated flux density 394+/-59mJy. More than 80% of the detected flux comes from extended (6"~2.2kpc) steep spectrum (alpha=-0.7) emission, likely from star formation in the molecular disk surrounding the two nuclei. We find elongated features extending 0.3" (110pc) and 0.9" (330pc) from the eastern and western nucleus respectively, which we interpret as evidence for outflows. The extent of radio emission requires acceleration of cosmic rays far outside the nuclei. We find that a simple three component model can explain most of the observed radio spectrum of the galaxy. When accounting for absorption at 1.4GHz, Arp 220 follows the FIR/radio correlation with q=2.36, and we estimate a star formation rate of 220M_{sun}_/yr. We derive thermal fractions at 1GHz of less than 1% for the nuclei, which indicates that a major part of the UV-photons are absorbed by dust. International LOFAR observations shows great promise to detect steep spectrum outflows and probe regions of thermal absorption. However, in LIRGs the emission detected at 150MHz does not necessarily come from the main regions of star formation. This implies that high spatial resolution is crucial for accurate estimates of star formation rates for such galaxies at 150MHz.
1186. Arp's Peculiar Galaxies
- ID:
- ivo://CDS.VizieR/VII/192
- Title:
- Arp's Peculiar Galaxies
- Short Name:
- VII/192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Halton C. Arp photographed 338 views of notable peculiar galaxies and published them as his 1966 "Atlas of Peculiar Galaxies." Since then, galaxy catalogs have named 585 of the involved galaxies. This contemporary index collects names and characteristics of the involved objects for use by contemporary observers of the historical views.
- ID:
- ivo://CDS.VizieR/J/A+A/562/A121
- Title:
- ARRAKIS: Atlas of Resonance Rings as Known In S4G
- Short Name:
- J/A+A/562/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Resonance rings and pseudorings (here collectively called "rings") are thought to be related to the gathering of material near dynamical resonances caused by non-axisymmetries in galaxy discs. Therefore, they are the consequence of secular evolution processes that redistribute material and angular momentum in discs. Their study may give clues on the formation and growth of bars and other disc non-axisymmetries. Our aims are to produce a Catalogue and an Atlas of the rings detected in the Spitzer Survey of Stellar Structure in Galaxies (S4G) and to conduct a statistical study of the data in the Catalogue. We traced the contours of rings previously identified by Buta et al. (in preparation) and fitted them with ellipses. We found the orientation of bars by studying the galaxy ellipse fits from S4G's Pipeline4. We used the galaxy orientation data obtained by S4G's Pipeline 4 to obtain intrinsic ellipticities and orientations of rings and the bars. ARRAKIS contains data on 724 ringed galaxies in the S4G. The frequency of resonance rings in the S4G is of 16+/-1% and 35+/-1% for outer and inner features, respectively. Outer rings are mostly found in Hubble stages -1<=T<=4. Inner rings are found in a broad distribution that covers the range -1<=T<=7. We confirm that outer rings have two preferred orientations, namely parallel and perpendicular to the bar. We confirm a tendency for inner rings to be oriented parallel to the bar, but we report the existence of a significant fraction (maybe as large as 50%) of inner features that have random orientations with respect to the bar. These misaligned inner rings are mostly found in late-type galaxies (T>=4). We find that the fraction of barred galaxies hosting outer (inner) rings is ~1.7 times (~1.3 times) that in unbarred galaxies. We confirm several results from previous surveys, as well as predictions from simulations of resonant rings and/or from manifold flux tube theory. We report that a significant fraction of inner rings in late-type galaxies have a random orientation with respect to the bar. This may be due to spiral modes decoupled from the bar dominating the Fourier amplitude spectrum at the radius of the inner ring. The fact that rings are only mildly favoured by bars suggests that those in unbarred galaxies either formed due to weak departures from the axisymmetry of the galactic potential or that they are born because of bars that have been destroyed after the ring formation.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A66
- Title:
- AR Sco VLA radio observations
- Short Name:
- J/A+A/611/A66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- AR Scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. Here we aim to investigate the multi-frequency radio emission of AR Sco in detail, in order to constrain its origin and emission mechanisms. We present interferometric radio frequency imaging of AR Sco at 1.5, 5 and 9GHz, analysing the total flux and polarization behaviour of this source at high time resolution (10, 3 and 3s), across a full 3.6h orbital period in each band. We find strong modulation of the radio flux on the orbital period and the orbital sideband of the white dwarf's spin period (also known as the "beat" period). This indicates that, like the optical flux, the radio flux arises predominantly from on or near the inner surface of the M-dwarf companion star. The beat-phase pulsations of AR Sco decrease in strength with decreasing frequency. They are strongest at 9GHz and at an orbital phase ~0.5. Unlike the optical emission from this source, radio emission from AR Sco shows weak linear polarization but very strong circular polarization, reaching ~30% at an orbital phase ~0.8. We infer the probable existence of a non-relativistic cyclotron emission component, which dominates at low radio frequencies. Given the required magnetic fields, this also likely arises from on or near the M-dwarf.
- ID:
- ivo://byu.arvo/tap
- Title:
- ArVO Byurakan TAP service
- Short Name:
- ArVO Byu TAP
- Date:
- 21 Feb 2020 09:33:52
- Publisher:
- The staff at the ArVO Data Center
- Description:
- The ArVO Byurakan's TAP end point. The Table Access Protocol (TAP) lets you execute queries against our database tables, inspect various metadata, and upload your own data. It is thus the VO's premier way to access public data holdings. Tables exposed through this endpoint include: columns, groups, key_columns, keys, schemas, tables from the tap_schema schema, main from the dfbsplates schema, spectra, ssa from the dfbsspec schema, obscore from the ivoa schema.
- ID:
- ivo://CDS.VizieR/J/A+A/487/383
- Title:
- Ar XVIII radiative and excitation rates
- Short Name:
- J/A+A/487/383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we report on calculations for energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the lowest 25 levels of the n<=5 configurations of H-like Ar XVIII. The general-purpose relativistic atomic structure package (GRASP) and Dirac atomic R-matrix code (DARC) are adopted for the calculations. Radiative rates, oscillator strengths, and line strengths are reported for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among the 25 levels. Furthermore, collision strengths and effective collision strengths are listed for all 300 transitions among the above 25 levels over a wide energy (temperature) range up to 800Ryd (10^7.4^K).
