- ID:
- ivo://CDS.VizieR/J/A+A/570/A113
- Title:
- Herschel/PACS imaging of {pi}^1^ Gru (HIP110478)
- Short Name:
- J/A+A/570/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Mass loss of Evolved StarS (MESS) sample observed with PACS on board the Herschel Space Observatory revealed that several asymptotic giant branch (AGB) stars are surrounded by an asymmetric circumstellar envelope (CSE) whose morphology is most likely caused by the interaction with a stellar companion. The evolution of AGB stars in binary systems plays a crucial role in understanding the formation of asymmetries in planetary nebulae (PNe), but at present, only a handful of cases are known where the interaction of a companion with the stellar AGB wind is observed. We probe the environment of the very evolved AGB star pi^1^ Gruis on large and small scales to identify the triggers of the observed asymmetries.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/565/A109
- Title:
- Herschel/PACS spectra of 48 evolved stars
- Short Name:
- J/A+A/565/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 48 Herschel/PACS spectra of evolved stars in the wavelength range of 67-72um. This wavelength range covers the 69mu band of crystalline olivine (Mg_2-2x_Fe_(2x)_SiO_4_). The width and wavelength position of this band are sensitive to the temperature and composition of the crystalline olivine. Our sample covers a wide range of objects: from high mass-loss rate AGB stars (OH/IR stars, dM/dt>=10^-5^M_{sun}_/yr), through post-AGB stars with and without circumbinary disks, to planetary nebulae and even a few massive evolved stars. The goal of this study is to exploit the spectral properties of the 69um band to determine the composition and temperature of the crystalline olivine. Since the objects cover a range of evolutionary phases, we study the physical and chemical properties in this range of physical environments. We fit the 69um band and use its width and position to probe the composition and temperature of the crystalline olivine. For 27 sources in the sample, we detected the 69um band of crystalline olivine (Mg_2-2x_Fe_(2x)_SiO_4_). The 69um band shows that all the sources produce pure forsterite grains containing no iron in their lattice structure. The temperature of the crystalline olivine as indicated by the 69um band, shows that on average the temperature of the crystalline olivine is highest in the group of OH/IR stars and the post-AGB stars with confirmed Keplerian disks. The temperature is lower for the other post-AGB stars and lowest for the planetary nebulae. A couple of the detected 69um bands are broader than those of pure magnesium-rich crystalline olivine, which we show can be due to a temperature gradient in the circumstellar environment of these stars. The disk sources in our sample with crystalline olivine are very diverse. They show either no 69um band, a moderately strong band, or a very strong band, together with a temperature for the crystalline olivine in their disk that is either very warm (~600K), moderately warm (~200K), or cold (~120K), respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/841/116
- Title:
- Herschel spectra of 11 very low mass stars
- Short Name:
- J/ApJ/841/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The properties of disks around brown dwarfs and very low mass stars (hereafter VLMOs) provide important boundary conditions on the process of planet formation and inform us about the numbers and masses of planets than can form in this regime. We use the Herschel Space Observatory PACS spectrometer to measure the continuum and [OI]63{mu}m line emission toward 11 VLMOs with known disks in the Taurus and Chamaeleon I star-forming regions. We fit radiative transfer models to the spectral energy distributions of these sources. Additionally, we carry out a grid of radiative transfer models run in a regime that connects the luminosity of our sources with brighter T Tauri stars. We find that VLMO disks with sizes 1.3-78au, smaller than typical T Tauri disks, fit well the spectral energy distributions assuming that disk geometry and dust properties are stellar mass independent. Reducing the disk size increases the disk temperature, and we show that VLMOs do not follow previously derived disk temperature-stellar luminosity relationships if the disk outer radius scales with stellar mass. Only 2 out of 11 sources are detected in [OI] despite a better sensitivity than was achieved for T Tauri stars, suggesting that VLMO disks are underluminous. Using thermochemical models, we show that smaller disks can lead to the unexpected [OI]63{mu}m nondetections in our sample. The disk outer radius is an important factor in determining the gas and dust observables.
- ID:
- ivo://CDS.VizieR/J/ApJ/887/105
- Title:
- Herschel/SPIRE FTS [CI] lines in KINGFISH gal.
- Short Name:
- J/ApJ/887/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present resolved [CI] line intensities of 18 nearby galaxies observed with the SPIRE FTS spectrometer on the Herschel Space Observatory. We use these data along with resolved CO line intensities from J_up_=1 to 7 to interpret what phase of the interstellar medium the [CI] lines trace within typical local galaxies. A tight, linear relation is found between the intensities of the CO(4-3) and [CI](2-1) lines; we hypothesize this is due to the similar upper level temperature of these two lines. We modeled the [CI] and CO line emission using large-velocity gradient models combined with an empirical template. According to this modeling, the [CI](1-0) line is clearly dominated by the low-excitation component. We determine [CI] to molecular mass conversion factors for both the [CI](1-0) and [CI](2-1) lines, with mean values of {alpha}_[CI](1-0)_=7.3M_{sun}_/K/km.s/pc^2^ and {alpha}_[CI](2-1)_=34M_{sun}_/K/km.s/pc^2^ with logarithmic root-mean-square spreads of 0.20 and 0.32dex, respectively. The similar spread of {alpha}_[CI](1-0)_ to {alpha}_CO_ (derived using the CO(2-1) line) suggests that [CI](1-0) may be just as good a tracer of cold molecular gas as CO(2-1) in galaxies of this type. On the other hand, the wider spread of {alpha}_[CI](2-1)_ and the tight relation found between [CI](2-1) and CO(4-3) suggest that much of the [CI](2-1) emission may originate in warmer molecular gas.
- ID:
- ivo://CDS.VizieR/J/ApJS/230/1
- Title:
- Herschel SPIRE/FTS 194-671um survey of GOALS LIRGs
- Short Name:
- J/ApJS/230/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a Herschel Space Observatory 194-671{mu}m spectroscopic survey of a sample of 121 local luminous infrared galaxies and report the fluxes of the CO J to J-1 rotational transitions for 4<=J<=13, the [NII] 205{mu}m line, the [CI] lines at 609 and 370{mu}m, as well as additional and usually fainter lines. The CO spectral line energy distributions (SLEDs) presented here are consistent with our earlier work, which was based on a smaller sample, that calls for two distinct molecular gas components in general: (i) a cold component, which emits CO lines primarily at J<~4 and likely represents the same gas phase traced by CO (1-0), and (ii) a warm component, which dominates over the mid-J regime (4<J<~10) and is intimately related to current star formation. We present evidence that the CO line emission associated with an active galactic nucleus is significant only at J>10. The flux ratios of the two [CI] lines imply modest excitation temperatures of 15-30K; the [CI] 370{mu}m line scales more linearly in flux with CO (4-3) than with CO (7-6). These findings suggest that the [CI] emission is predominantly associated with the gas component defined in (i) above. Our analysis of the stacked spectra in different far-infrared (FIR) color bins reveals an evolution of the SLED of the rotational transitions of H_2_O vapor as a function of the FIR color in a direction consistent with infrared photon pumping.
- ID:
- ivo://CDS.VizieR/J/A+A/573/A129
- Title:
- HeViCS. SPIRE point-source catalogs
- Short Name:
- J/A+A/573/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present three independent catalogs of point-sources extracted from SPIRE images at 250, 350, and 500 micron, acquired with the Herschel Space Observatory as a part of the Herschel Virgo Cluster Survey (HeViCS). The catalogs have been cross-correlated to consistently extract the photometry at SPIRE wavelengths for each object. Sources have been detected using an iterative loop. The source positions are determined by estimating the likelihood to be a real source for each peak on the maps, according to the criterion defined in the sourceExtractorSussextractor task. The flux densities are estimated using the sourceExtractorTimeline, a timeline-based point source fitter that also determines the fitting procedure with the width of the Gaussian that best reproduces the source considered. Afterwards, each source is subtracted from the maps, removing a Gaussian function in every position with the full width half maximum equal to that estimated in sourceExtractorTimeline.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A114
- Title:
- Hi-GAL cluster candidates physical properties
- Short Name:
- J/A+A/597/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aims are to investigate the clustering of the far-infrared sources from the Herschel infrared Galactic Plane Survey (Hi-GAL) in the Galactic longitude range of -71 to 67{deg}. These clumps, and their spatial distribution, are an imprint of the original conditions within a molecular cloud. This will produce a catalogue of over-densities. The minimum spanning tree (MST) method was used to identify the over-densities in two dimensions. The catalogue was further refined by folding in heliocentric distances, resulting in more reliable over-densities, which are cluster candidates. We found 1633 over-densities with more than ten members. Of these, 496 are defined as cluster candidates because of the reliability of the distances, with a further 1,137 potential cluster candidates. The spatial distributions of the cluster candidates are different in the first and fourth quadrants, with all clusters following the spiral structure of the Milky Way. The cluster candidates are fractal. The clump mass functions of the clustered and isolated are statistically indistinguishable from each other and are consistent with Kroupa's initial mass function.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/100
- Title:
- Hi-GAL compact source catalog. -71.0<l<67.0
- Short Name:
- J/MNRAS/471/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hi-GAL (Herschel InfraRed Galactic Plane Survey) is a large-scale survey of the Galactic plane, performed with Herschelin five infrared continuum bands between 70 and 500{mu}m. We present a band-merged catalogue of spatially matched sources and their properties derived from fits to the spectral energy distributions (SEDs) and heliocentric distances, based on the photometric catalogues presented in Molinari et al., covering the portion of Galactic plane -71.0{deg}<l<67.0{deg}. The band-merged catalogue contains 100 922 sources with a regular SED, 24584 of which show a 70-{mu}m counterpart and are thus considered protostellar, while the remainder are considered starless. Thanks to this huge number of sources, we are able to carry out a preliminary analysis of early stages of star formation, identifying the conditions that characterize different evolutionary phases on a statistically significant basis. We calculate surface densities to investigate the gravitational stability of clumps and their potential to form massive stars. We also explore evolutionary status metrics such as the dust temperature, luminosity and bolometric temperature, finding that these are higher in protostellar sources compared to pre-stellar ones. The surface density of sources follows an increasing trend as they evolve from pre-stellar to protostellar, but then it is found to decrease again in the majority of the most evolved clumps. Finally, we study the physical parameters of sources with respect to Galactic longitude and the association with spiral arms, finding only minor or no differences between the average evolutionary status of sources in the fourth and first Galactic quadrants, or between 'on-arm' and 'interarm' positions.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A149
- Title:
- Hi-GAL. inner Milky Way: +68>=l>=70
- Short Name:
- J/A+A/591/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500{mu}m, encompassing the peak of the spectral energy distribution of cold dust for 8<~T<~50K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68{deg}>~l>~-70{deg} in a |b|<=1{deg} latitude strip. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2{deg}x2{deg} "tile" that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared. Hi-GAL DR1 images are cirrus noise limited and reach the 1{sigma}-rms predicted by the Herschel Time Estimators for parallel-mode observations at 60"/s scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source position, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 120581, 291858, 280143, 161946, and 85811 compact sources in the five bands.
- ID:
- ivo://CDS.VizieR/J/ApJ/817/2
- Title:
- High angular resolution spectroscopy of NGC 1277
- Short Name:
- J/ApJ/817/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nearby lenticular galaxy NGC 1277 is thought to host one of the largest black holes known, however the black hole mass measurement is based on low spatial resolution spectroscopy. In this paper, we present Gemini Near-infrared Integral Field Spectrometer observations assisted by adaptive optics. We map out the galaxy's stellar kinematics within ~440pc of the nucleus with an angular resolution that allows us to probe well within the region where the potential from the black hole dominates. We find that the stellar velocity dispersion rises dramatically, reaching ~550km/s at the center. Through orbit-based, stellar-dynamical models we obtain a black hole mass of (4.9+/-1.6)x10^9^M_{sun}_ (1{sigma} uncertainties). Although the black hole mass measurement is smaller by a factor of ~3 compared to previous claims based on large-scale kinematics, NGC 1277 does indeed contain one of the most massive black holes detected to date, and the black hole mass is an order of magnitude larger than expectations from the empirical relation between black hole mass and galaxy luminosity. Given the galaxy's similarities to the higher redshift (z~2) massive quiescent galaxies, NGC 1277 could be a relic, passively evolving since that period. A population of local analogs to the higher redshift quiescent galaxies that also contain over-massive black holes may suggest that black hole growth precedes that of the host galaxy.
