- ID:
- ivo://CDS.VizieR/J/ApJS/232/3
- Title:
- Spectral line surveys of 30 regions
- Short Name:
- J/ApJS/232/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectral line surveys are an indispensable tool for exploring the physical and chemical evolution of astrophysical environments due to the vast amount of data that can be obtained in a relatively short amount of time. We present deep, broadband spectral line surveys of 30 interstellar clouds using two broadband {lambda}=1.3mm receivers at the Caltech Submillimeter Observatory. This information can be used to probe the influence of physical environment on molecular complexity. We observed a wide variety of sources to examine the relative abundances of organic molecules as they relate to the physical properties of the source (i.e., temperature, density, dynamics, etc.). The spectra are highly sensitive, with noise levels <=25mK at a velocity resolution of ~0.35km/s. In the initial analysis presented here, column densities and rotational temperatures have been determined for the molecular species that contribute significantly to the spectral line density in this wavelength regime. We present these results and discuss their implications for complex molecule formation in the interstellar medium.
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Search Results
- ID:
- ivo://CDS.VizieR/III/40A
- Title:
- Spectral Survey of Southern Milky Way
- Short Name:
- III/40A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectral survey, carried out at the Stockholm Observatory, was initiated by B. Lindblad. The observational material was obtained by L.O. Loden, K. Loden and others in the years 1956-1965, when the Stockholm Observatory took part in a joint enterprise for using the Harvard-Boyden station. The Swedish Natural Science Research Council, the Royal Academy of the Sciences, and the K. and A. Wallenberg Foundation funded the observations, which are based on both direct and objective prism plates. The data were published in three parts, the first having less precise positions than the others. The coordinates for Catalogue I (3033) were later recomputed with the same reduction procedure as Catalogues II (3034) and III (3035), making the present catalogue uniform (Andersen, 1977). The files include star identification, finding chart identification, RA and Dec, galactic longitude and latitude, spectral type, blue magnitude, visual magnitude and remarks. The data concerning the part 2 were revised by Brian Skiff in November 1996 (see the "History" section below)
- ID:
- ivo://CDS.VizieR/J/A+A/614/A135
- Title:
- Spectra of 78 PN central stars
- Short Name:
- J/A+A/614/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There are more than 3000 known Galactic planetary nebulae (PNe), but only 492 central stars of Galactic planetary nebulae (CSPN) have known spectral types. It is vital to increase this number in order to have reliable statistics, which will lead to an increase of our understanding of these amazing objects. We aim to contribute to the knowledge of central stars of planetary nebulae and stellar evolution. This observational study is based on Gemini Multi-Object Spectrographs (GMOS) and with the Intermediate Dispersion Spectrograph (IDS) at the Isaac Newton Telescope (INT) spectra of 78 CSPN. The objects were selected because they did not have any previous classification, or the present classification is ambiguous. These new high quality spectra allowed us to identify the key stellar lines for determining spectral classification in the Morgan-Keenan (MK) system. We have acquired optical spectra of a large sample of CSPN. From the observed targets, 50 are classified here for the first time while for 28 the existing classifications have been improved. In seven objects we have identified a P-Cygni profile at the HeI lines. Six of these CSPN are late O-type. The vast majority of the stars in the sample exhibit an absorption-type spectrum, and in one case we have found wide emission lines typical of [WR] stars. We give a complementary, and preliminary, classification criterion to obtain the sub-type of the O(H)-type CSPN. Finally, we give a more realistic value of the proportion of CSPN that are rich or poor in hydrogen.
- ID:
- ivo://CDS.VizieR/J/ApJ/690/1358
- Title:
- Spectra of unusual optical transient SCP 06F6
- Short Name:
- J/ApJ/690/1358
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of SCP 06F6, an unusual optical transient discovered during the Hubble Space Telescope Cluster Supernova Survey. The transient brightened over a period of ~100 days, reached a peak magnitude of ~21.0 in both i_775_ and z_850_, and then declined over a similar timescale. There is no host galaxy or progenitor star detected at the location of the transient to a 3{sigma} upper limit of i_775_>=26.4 and z_850_>=26.1, giving a corresponding lower limit on the flux increase of a factor of ~120. Multiple spectra show five broad absorption bands between 4100{AA} and 6500{AA}, and a mostly featureless continuum longward of 6500{AA}. The shape of the light curve is inconsistent with microlensing. The transient's spectrum, in addition to being inconsistent with all known supernova types, does not match any spectrum in the Sloan Digital Sky Survey database. We suggest that the transient may be one of a new class.
- ID:
- ivo://CDS.VizieR/J/A+A/569/A120
- Title:
- Spectra of wide companions to planet-host stars
- Short Name:
- J/A+A/569/A120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for wide companions to planet-host stars to improve our knowledge on their multiplicity at wide physical separations. We cross-matched approximately 6200 square degree area of the Southern sky imaged by the Visible Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) with the Two Micron All Sky Survey (2MASS) to look for wide common proper motion companions to known planet-host stars. We complemented our astrometric search with photometric criteria. We confirmed spectroscopically the co-moving nature of seven sources out of 16 companion candidates and discarded eight, while the remaining one stays as a candidate. Among these new wide companions to planet-host stars, we discovered a T4.5 dwarf companion at 6.3-arcmin (~9000AU) from HIP70849, a K7V star which hosts a 9 Jupiter mass planet with an eccentric orbit. We also report two new stellar M dwarf companions to one G and one metal-rich K star. We infer stellar and substellar binary frequencies for our complete sample of 37 targets of 5.4+/-3.8% and 2.7+/-2.7% (1 sigma confidence level), respectively, for projected physical separations larger than ~60-160AU assuming the range of distances of planet-host stars (24-75pc). These values are comparable to the frequencies of non planet-host stars. We find that the period-eccentricity trend holds with a lack of multiple systems with planets at large eccentricities (e>0.2) for periods less than 40-days. However, the lack of planets more massive than 2.5 Jupiter masses and short periods (<40-days) orbiting single stars is not so obvious due to recent discoveries by ground-based transit surveys and space missions.
- ID:
- ivo://CDS.VizieR/J/ApJ/668/839
- Title:
- Spectrophotometric redshifts for 1308 HUDF galaxies
- Short Name:
- J/ApJ/668/839
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of spectrophotometric redshifts for 1308 galaxies from the Grism ACS Program for Extragalactic Science (GRAPES) observations with the Hubble Space Telescope. These low-resolution spectra between 6000{AA} and 9500{AA} are supplemented with U, J, H, and Ks data from various facilities, resulting in redshifts computed with ~40 spectral bins per galaxy. For 75 galaxies in the range 0.5<z<1.5 with spectroscopic redshifts, the standard deviation in the fractional error in 1+z is 0.037. With this catalog, we compute the B-band luminosity function in this redshift range from 72 galaxies. Due to the depth of the GRAPES survey, we are able to accurately constrain the faint-end slope by going to MB~-18mag at z=1.0+/-0.2, nearly 2mag fainter than previous studies. The faint-end slope is alpha=-1.32+/-0.07. When compared to numerous published values at various redshifts, we find strong evidence for a steepening of the faint-end slope with redshift, which is expected in the hierarchical formation scenario of galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/157
- Title:
- Spectrophotometric redshifts of GOODS galaxies
- Short Name:
- J/ApJ/883/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the accuracy of 4000{AA}/Balmer-break based redshifts by combining Hubble Space Telescope (HST) grism data with photometry. The grism spectra are from the Probing Evolution And Reionization Spectroscopically survey with HST using the G800L grism on the Advanced Camera for Surveys. The photometric data come from a compilation by the 3D-HST collaboration of imaging from multiple surveys (notably, the Cosmic Assembly Near-infrared Deep Extragalactic Survey (CANDELS) and 3D-HST). We show evidence that spectrophotometric redshifts (SPZs) typically improve the accuracy of photometric redshifts by ~17%-60%. Our SPZ method is a template-fitting-based routine that accounts for correlated data between neighboring points within grism spectra via the covariance matrix formalism and also accounts for galaxy morphology along the dispersion direction. We show that the robustness of the SPZ is directly related to the fidelity of the D4000 measurement. We also estimate the accuracy of continuum-based redshifts, i.e., for galaxies that do not contain strong emission lines, based on the grism data alone ({sigma}_{Delta}z/(1+z)_^NMAD^<~0.06). Given that future space-based observatories like Wide Field InfraRed Survey Telescope and Euclid will spend a significant fraction of time on slitless spectroscopic observations, we estimate number densities for objects with |{Delta}z/(1+z_s_)|<=0.02. We predict ~700-4400 galaxies degree^-2^ for galaxies with D4000>1.1 and |{Delta}z/(1+z_s_)|<=0.02 to a limiting depth of i_AB_=24mag. This is especially important in the absence of an accompanying rich photometric data set like the existing one for the CANDELS fields, where redshift accuracy from future surveys will rely only on the presence of a feature like the 4000{AA}/Balmer breaks or the presence of emission lines within the grism spectra.
- ID:
- ivo://CDS.VizieR/J/ApJ/695/1591
- Title:
- Spectrophotometry in PEARS fields
- Short Name:
- J/ApJ/695/1591
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep ACS slitless grism observations and identification of stellar sources are presented within the Great Observatories Origins Deep Survey North and South fields which were obtained in the Probing Evolution And Reionization Spectroscopically (PEARS) program. It is demonstrated that even low-resolution spectra can be a very powerful means of identifying stars in the field, especially low-mass stars with stellar types M0 and later. The PEARS fields lay within the larger GOODS fields, and we used new, deeper images to further refine the selection of stars in the PEARS field, down to a magnitude of z_850_=25 using a newly developed stellarity parameter. The total number of stars with reliable spectroscopic and morphological identification was 95 and 108 in the north and south fields, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJS/126/331
- Title:
- Spectrophotometry of nearby field galaxies
- Short Name:
- J/ApJS/126/331
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained integrated and nuclear spectra as well as U, B, R surface photometry for a representative sample of 196 nearby galaxies. These galaxies span the entire Hubble sequence in morphological type, as well as a wide range of luminosities (M_B_=-14 to -22). Here we present the spectrophotometry for these galaxies. The selection of the sample and the U, B, R surface photometry is described in a companion paper (J/ApJS/126/271).
- ID:
- ivo://CDS.VizieR/J/ApJ/815/49
- Title:
- Spectropolarimetric survey of radio sources
- Short Name:
- J/ApJ/815/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ~1' resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.
