- ID:
- ivo://CDS.VizieR/J/ApJ/705/32
- Title:
- Diffuse interstellar bands from HD 183143
- Short Name:
- J/ApJ/705/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Echelle spectra of HD 183143 [B7Iae, E(B-V)=1.27] were obtained on three nights, at a resolving power R=38000 and with a signal-to-noise ratio ~1000 at 6400{AA} in the final, combined spectrum. A catalog is presented of 414 diffuse interstellar bands (DIBs) measured between 3900 and 8100{AA} in this spectrum. The central wavelengths, the widths (FWHM), and the equivalent widths of nearly all of the bands are tabulated, along with the minimum uncertainties in the latter. Among the 414 bands, 135 (or 33%) were not reported in four previous, modern surveys of the DIBs in the spectra of various stars, including HD 183143. The principal result of this study is that the great majority of the bands in the catalog are very weak and fairly narrow. Typical equivalent widths amount to a few m{AA}, and the bandwidths (FWHM) are most often near 0.7{AA}.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/429/559
- Title:
- Diffuse Interstellar Bands in NGC 1448
- Short Name:
- J/A+A/429/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic VLT/UVES observations of two emerging supernovae, the Type Ia SM 2001el and the Type II SN 2003hn, in the spiral galaxy NGC 1448. Our high resolution and high signal-to-noise spectra display atomic lines of Ca II, Na I, Ti II and K I in the host galaxy. In the line of sight towards SN 2001el, we also detect over a dozen diffuse interstellar bands (DIBs) within NGC 1448.
- ID:
- ivo://CDS.VizieR/J/MNRAS/358/563
- Title:
- Diffuse Interstellar Bands in 49 stars
- Short Name:
- J/MNRAS/358/563
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We relate the equivalent widths of 11 diffuse interstellar bands, measured in the spectra of 49 stars, to different colour excesses in the ultraviolet. We find that most of the observed bands correlate positively with the extinction in the neighbourhood of the 2175{AA} bump. Correlation with colour excesses in other parts of the extinction curve is more variable from one diffuse interstellar band to another; we find that some diffuse bands (5797, 5850 and 6376{AA}) correlate positively with the overall slope of the extinction curve, while others (5780 and 6284{AA}) exhibit negative correlation. We discuss the implications of these results on the links between the diffuse interstellar band carriers and the properties of the interstellar grains.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A136
- Title:
- Diffuse Interstellar Bands in 150 stars
- Short Name:
- J/A+A/544/A136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Diffuse interstellar bands (DIBs) measured in stellar spectra contain information on the amount of interstellar (IS) matter that is distributed along the line-of-sight, and similarly to other absorbing species may be used to locate IS clouds. Here we present a new database of 5780.5 and 6283.8{AA} DIB measurements. Those two DIBs have the advantage that they are strong and also broad enough to be detectable in cool-star spectra. We also study their correlation with the reddening.
- ID:
- ivo://CDS.VizieR/J/ApJ/708/1628
- Title:
- Diffuse interstellar bands. IV.
- Short Name:
- J/ApJ/708/1628
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a sample of 114 diffuse cloud sightlines spanning a wide range of interstellar environments, we find the equivalent widths of the diffuse interstellar bands (DIBs) {lambda}6196.0 and {lambda}6613.6 to be extremely well correlated, with a correlation coefficient of 0.986. A maximum likelihood functional relationship analysis shows that the observations are consistent with a perfect correlation if the observational errors, which are dominated by continuum placement and other systematics such as interfering lines, have been underestimated by a factor of 2. The quality of this correlation far exceeds other previously studied correlations, such as that between the {lambda}5780.5 DIB and either the color excess or the atomic hydrogen column density. The unusually tight correlation between these two DIBs would seem to suggest that they might represent the first pair of DIBs known to be due to the same molecular carrier. However, further theoretical work will be required to determine whether the different linewidths and band shapes of these two DIBs can be consistent with a common carrier. If the two DIBs do not in fact share the same molecular carrier, their two carriers must be chemically very closely related.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/45.261
- Title:
- Diffuse ionized gas database DIGEDA
- Short Name:
- J/other/RMxAA/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of the Diffuse Ionized Gas (DIG) have progressed without providing so far any strict criterion to distinguish DIGs from HII regions. In this work, we compile the emission line measurements of 29 galaxies that are available in the scientific literature, thereby setting up the first DIG database DIGEDA. Making use of this database, we proceeded to analyze global properties of the DIG using the [NII]6583/Halpha, [OI]6300/Halpha, [OIII]5007/Hbeta and [SII]6716/Halpha lines ratios, including the Halpha emission measure. This analysis leads us to conclude that the [NII]/Halpha ratio provides an objective criterion for distinguishing whether an emission region is DIG or an HII region, while the EM(Halpha) is a useful quantity only when the galaxies are considered individually. Finally, we find that the emission regions of Irr galaxies classified as DIG in the literature appear in fact to be much more similar to HII regions than to the DIGs of spiral galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A95
- Title:
- Diffuse ionized gas in the Antennae galaxy
- Short Name:
- J/A+A/611/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect HII regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of HII regions, showing fainter luminosities. By comparing HII region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each HII region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking HII regions for the diffuse ionized gas in the Antennae.
- ID:
- ivo://CDS.VizieR/J/ApJS/202/14
- Title:
- Diffuse OVII and OVIII emission from XMM
- Short Name:
- J/ApJS/202/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all-sky catalog of diffuse OVII and OVIII line intensities, extracted from archival XMM-Newton observations. This catalog supersedes our previous catalog (Henley et al., 2010, Cat. J/ApJS/187/388), which covered the sky between l=120{deg} and l=240{deg}. We attempted to reduce the contamination from near-Earth solar wind charge exchange (SWCX) emission by excluding times of high solar wind proton flux from the data. Without this filtering, we were able to extract measurements from 1868 observations. With this filtering, nearly half of the observations became unusable, and only 1003 observations yielded measurements. The OVII and OVIII intensities are typically ~2-11 and <~3 photons/cm^2^/s/sr (line unit, L.U.), respectively, although much brighter intensities were also recorded. Our data set includes 217 directions that have been observed multiple times by XMM-Newton. The time variation of the intensities from such directions may be used to constrain SWCX models.
- ID:
- ivo://CDS.VizieR/J/AJ/155/81
- Title:
- Diffuse X-ray-emitting gas in major mergers
- Short Name:
- J/AJ/155/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using archived data from the Chandra X-ray telescope, we have extracted the diffuse X-ray emission from 49 equal-mass interacting/merging galaxy pairs in a merger sequence, from widely separated pairs to merger remnants. After the removal of contributions from unresolved point sources, we compared the diffuse thermal X-ray luminosity from hot gas (L_X_(gas)) with the global star formation rate (SFR). After correction for absorption within the target galaxy, we do not see a strong trend of L_X_(gas)/SFR with the SFR or merger stage for galaxies with SFR>1 M_{sun}_/yr. For these galaxies, the median L_X_(gas)/SFR is 5.5x10^39^ ((erg/s)/M_{sun}_/yr), similar to that of normal spiral galaxies. These results suggest that stellar feedback in star-forming galaxies reaches an approximately steady-state condition, in which a relatively constant fraction of about 2% of the total energy output from supernovae and stellar winds is converted into X-ray flux. Three late-stage merger remnants with low SFRs and high K-band luminosities (L_K_) have enhanced L_X_(gas)/SFR; their UV/IR/optical colors suggest that they are post-starburst galaxies, perhaps in the process of becoming ellipticals. Systems with L_K_<10^10^ L_{sun}_ have lower L_X_(gas)/SFR ratios than the other galaxies in our sample, perhaps due to lower gravitational fields or lower metallicities. We see no relation between L_X_(gas)/SFR and Seyfert activity in this sample, suggesting that feedback from active galactic nuclei is not a major contributor to the hot gas in our sample galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/500/1059
- Title:
- Dimethyl ether transitions frequencies
- Short Name:
- J/ApJ/500/1059
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dimethyl ether (CH_3_OCH_3_) is a well-known interstellar molecule with a large abundance in hot core regions. We have measured many rotational-torsional transition lines of this molecule in the 100-550GHz frequency range using two experimental techniques: a klystron-based traditional millimeter-wave spectrometer and a new fast scan spectrometer (designated "FASSST") with a voltage-tunable backward wave oscillator. The lines arising from the ground vibrational state have been combined with previous data, mainly at lower frequencies, to form a global data set consisting of over 1600 lines that have been assigned and fitted by an effective Hamiltonian method. The spectral constants obtained from the fit allow us to predict the frequencies of almost 6000 additional lines of dimethyl ether through 600GHz.
