- ID:
- ivo://CDS.VizieR/J/A+A/466/1099
- Title:
- N-band visibilities of V Oph
- Short Name:
- J/A+A/466/1099
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first multi-epoch N-band spectro-interferometric observations of the carbon-rich Mira variable V Oph using MIDI at the ESO's Very Large Telescope Interferometer. Our aim is to study temporal variations of physical properties of the outer atmosphere and the circumstellar dust shell based on spectrally-dispersed N-band visibilities over the C_2_H_2_ (+HCN) features and the dust emission.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/AstBu/68.53
- Title:
- Nearby multiple Speckle interferometry. V.
- Short Name:
- J/other/AstBu/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of speckle interferometric observations of 194 binary stars performed at the BTA 6m telescope in 2002-2006 are presented in this paper. For speckle observations we used filters with central wavelengths from 545 to 800nm and speckle camera with the fast CCD coupled with a tree-chamber intensifier. The most part of the observed systems (80 stars) - pairs, which binarity was discovered by Hipparcos satellite fo the first time. And the other stars are visual binaries and interferometric binary systems which orbital periods estimates from several to ten of the year. The pairs with slow orbital motion are included to the observation list, also. They are used for position parameters calibrations.
- ID:
- ivo://CDS.VizieR/J/AJ/144/7
- Title:
- Near-IR imaging of Hipparcos astrometric binaries
- Short Name:
- J/AJ/144/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A subset of 51 Hipparcos astrometric binaries among FG dwarfs within 67pc has been surveyed with the Near-Infrared Coronagraphic Imager adaptive optics system at Gemini-S, directly resolving for the first time 17 subarcsecond companions and 7 wider ones. Using these data together with published speckle interferometry of 57 stars, we compare the statistics of resolved astrometric companions with those of a simulated binary population. The fraction of resolved companions is slightly lower than expected from binary statistics. About 10% of astrometric companions could be "dark" (white dwarfs and close pairs of late M-dwarfs). To our surprise, several binaries are found with companions too wide to explain the acceleration. Re-analysis of selected intermediate astrometric data shows that some acceleration solutions in the original Hipparcos catalog are spurious.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/158
- Title:
- Near-IR interferometry of nova Vul 2007
- Short Name:
- J/ApJ/755/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the Palomar Testbed Interferometer (PTI) to resolve 2.2{mu}m emission from the classical nova V458 Vul 2007 over the course of several days following its discovery on 2007 August 8.54 UT. We also obtained K-band photometric data and spectra of the nova during the early days of the outburst. We also used photometric measurements from the AAVSO database. This is a unique data set offering a three-technique approach: high-resolution imaging, spectroscopy, and photometry. Our analysis shows that the nova ejecta can be modeled as an inclined disk at low inclination, i.e., low ellipticity which is consistent with the nova being in the fireball phase at which the outflowing gas is optically thick, confirmed by the presence of strong P-Cygni Balmer lines in the spectra. The expansion velocity is {approx}1700km/s, derived from the H{alpha} line. By combining the nova's angular expansion rate measured by PTI with the expansion rate measured from spectroscopy, the inferred distance to the nova is 9.9-11.4kpc. We also used the K-band fluxes and the derived size of the emission to estimate the total mass ejected from the nova {approx}4x10^-4^M_{sun}_. The quick transition of the nova from Fe II to He/N class makes V458 Vul 2007 a hybrid nova.
- ID:
- ivo://CDS.VizieR/J/PASP/110/1012
- Title:
- New double stars from HST
- Short Name:
- J/PASP/110/1012
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data from the Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) interferometers, covering 22 months of guide-star acquisition operations, have been analyzed for evidence of stellar duplicity. The data comprise a survey of observed guide stars, all of which are taken from the HST Guide Star Catalog, ranging in magnitude from 9 to 14. The survey results cover a parameter space for the newly found doubles, for the fainter stars, which are of smaller limiting angular separations than in any previous surveys. The normal HST engineering telemetry data from 13,979 acquisitions on 4882 stars have been processed. The FGS guidance data can reveal duplicity with separations ranging from approximately 30mas, for the brighter stars, with small magnitude differences, up to the neighborhood of 500mas, and in some cases to 1000mas. The fraction of guide stars indicating duplicity is a function of the statistical criteria used but is over 5% at a very high level of confidence. It is possible that if some of the brighter and closer pairs could be identified as nearby, then their orbital motions would be rapid enough to allow a mass and distance determination on a timescale of a decade if followed with ground-based interferometric and spectroscopic instruments. A brief catalog of doubles is given, nearly all of which are of certain duplicity. Information for accessing on-line catalogs of large numbers of stars with lesser, but nevertheless strong, probabilities of duplicity and also for the solutions for duplicity from all acquisitions is provided.
- ID:
- ivo://CDS.VizieR/J/A+A/582/A91
- Title:
- NGC 4418 ALMA mm-wave spectral scan
- Short Name:
- J/A+A/582/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extragalactic observations allow the study of molecular chemistry and excitation under physical conditions which may differ greatly from what found in the Milky Way. The compact, obscured nuclei (CON) of luminous infrared galaxies (LIRG) combine large molecular columns with intense infrared (IR), ultra-violet (UV) and X- radiation and represent ideal laboratories to study the chemistry of the interstellar medium (ISM) under extreme conditions. To obtain for the first time a multi-band spectral scan of a LIRG, in order to derive the molecular abundances and excitation, to be compared to other Galactic and extragalactic environments. We obtained an ALMA Cycle 0 spectral scan of the dusty LIRG NGC 4418, spanning a total of 70.7GHz in bands 3, 6, and 7. We use a combined local thermal equilibrium (LTE) and non-LTE (NLTE) fit of the spectrum in order to identify the molecular species and derive column densities and excitation temperatures. We derive molecular abundances and compare them with other Galactic and extragalactic sources by means of a principal component analysis.
177. NGC 3269 CO spectra
- ID:
- ivo://CDS.VizieR/J/A+A/645/A36
- Title:
- NGC 3269 CO spectra
- Short Name:
- J/A+A/645/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An intriguing silhouette of a small dust patch can be seen against the disk of the S0 galaxy NGC 3269 in the Antlia cluster in optical images. The images do not provide any clue as to whether the patch is a local Jupiter mass-scale cloudlet or a large extragalactic dust complex. We aim to resolve the nature of this object: is it a small Galactic cloudlet or an extragalactic dust complex? ALMA and APEX spectroscopy and Gemini GMOS long-slit spectroscopy were used to measure the velocity of the patch and the NGC 3269 disk radial velocity curve. A weak 16+/-2.5km/s wide ^12^CO (2-1) T_MB_ 19+/-2.5mK line in a 2.2" by 2.12" beam associated with the object was detected with ALMA. The observed heliocentric velocity, V_r,hel_=3878+/-5.0km/s, immediately establishes the extragalactic nature of the object. The patch velocity is consistent with the velocity of the nucleus of NGC 3269, but not with the radial velocity of the NGC 3269 disk of the galaxy at its position. The ~4" angular size of the patch corresponds to a linear size of ~1kpc at the galaxy's Hubble distance of 50.7Mpc. The mass estimated from the ^12^CO (2-1) emission is ~1.4x10^6^(d/50.7Mpc)^2^M_{sun}_, while the attenuation derived from the optical spectrum implies a dust mass of ~2.6x10^4^(d/50.7Mpc)^2^M_{sun}_. The derived attenuation ratio A'_B_/(A'_B_-A'_R_) of 1.6+/-0.11 is substantially lower than the corresponding value for the mean Milky Way extinction curve for point sources (2.3). We established the extragalactic nature of the patch, but its origin remains elusive. One possibility is that the dust patch is left over from the removal of interstellar matter in NGC 3269 through the interaction with its neighbour, NGC 3268.
- ID:
- ivo://CDS.VizieR/J/A+A/568/A65
- Title:
- NGC 7129 FIRS 2 interferometric 1-D spectrum
- Short Name:
- J/A+A/568/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 7129 FIRS 2 (hereafter FIRS 2) is an intermediate-mass (2 to 8M_{sun}_) protostar located at a distance of 1250pc. High spatial resolution observations are required to resolve the hot core at its center. We present a molecular survey from 218200MHz to 221800MHz carried out with the IRAM Plateau de Bure Interferometer. These observations were complemented with a long integration single-dish spectrum taken with the IRAM 30m telescope. We used a Local Thermodynamic Equilibrium (LTE) single temperature code to model the whole dataset. The interferometric spectrum is crowded with a total of ~300 lines from which a few dozens remain unidentified yet. The spectrum has been modeled with a total of 20 species and their isomers, isotopologues and deuterated compounds. Complex molecules like methyl formate (CH_3_OCHO), ethanol (CH_3_CH_2_OH),g lycolaldehyde (CH_2_OHCHO), acetone (CH_3_COCH_3_), dimethyl ether (CH_3_OCH_3_), ethyl cyanide (CH_3_CH_2_CN) and the aGg' conformer of ethylene glycol (aGg'-(CH_2_OH)_2_) are among the detected species. The detection of vibrationally excited lines of CH_3_CN, CH_3_OCHO, CH_3_OH, OCS, HC_3_N and CH_3_CHO proves the existence of gas and dust at high temperatures. In fact, the gas kinetic temperature estimated from the vibrational lines of CH_3_CN, ~405K, is similar to that measured in massive hot cores. Our data allow an extensive comparison of the chemistry in FIRS 2 and the Orion hot core. We find a quite similar chemistry in FIRS 2 and Orion. Most of the studied fractional molecular abundances agree within a factor of 5. Larger differences are only found for the deuterated compounds D_2_CO and CH_2_DOH and a few molecules (CH_3_CH_2_CN, SO_2_, HNCO and CH_3_CHO). Since the physical conditions are similar in both hot cores, only different initial conditions (warmer pre-collapse phase in the case of Orion) and/or different crossing time of the gas in the hot core can explain this behavior.
- ID:
- ivo://CDS.VizieR/J/A+A/634/A1
- Title:
- NGC 1068 GRAVITY reconstructed image
- Short Name:
- J/A+A/634/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared interferometric data on the Seyfert 2 galaxy NGC 1068, obtained with the GRAVITY instrument on the European Southern Observatory Very Large Telescope Interferometer. The extensive baseline coverage from 5 to 60M{lambda} allowed us to reconstruct a continuum image of the nucleus with an unrivaled 0.2pc resolution in the K-band.We find a thin ring-like structure of emission with a radius r=0.24+/-0.03pc, inclination i=70+/-5{deg}, position angle PA=-50+/-4{deg}, and h/r<0.14, which we associate with the dust sublimation region. The observed morphology is inconsistent with the expected signatures of a geometrically and optically thick torus. Instead, the infrared emission shows a striking resemblance to the 22GHz maser disc, which suggests they share a common region of origin. The near-infrared spectral energy distribution indicates a bolometric luminosity of (0.4-4.7)x10^45^erg/s, behind a large A_K_~=5.5 (A_V_~=90) screen of extinction that also appears to contribute significantly to obscuring the broad line region.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A78
- Title:
- NGC1068 interferometric mid-IR measurements
- Short Name:
- J/A+A/602/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent NuSTAR observations revealed a somewhat unexpected increase in the X-ray flux of the nucleus of NGC 1068. We expect the infrared emission of the dusty torus to react on the intrinsic changes of the accretion disk. We aim to investigate the origin of the X-ray variation by investigating the response of the mid-infrared environment. We obtained single-aperture and interferometric mid-infrared measurements and directly compared the measurements observed before and immediately after the X-ray variations. The average correlated and single-aperture fluxes as well as the differential phases were directly compared to detect a possible change in the structure of the nuclear emission on scales of ~2pc. The flux densities and differential phases of the observations before and during the X-ray variation show no significant change over a period of ten years. Possible minor variations in the infrared emission are ~6%. Our results suggest that the mid-infrared environment of NGC 1068 has remained unchanged for a decade. The recent transient change in the X-rays did not cause a significant variation in the infrared emission. This independent study supports previous conclusions that stated that the X-ray variation detected by NuSTAR observations is due to X-ray emission piercing through a patchy section of the dusty region.
