- ID:
- ivo://CDS.VizieR/J/A+A/441/981
- Title:
- HII regions in 5 spiral galaxies
- Short Name:
- J/A+A/441/981
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained spectroscopic observations from 3600{AA} to 9200{AA} with FORS at the Very Large Telescope for approximately 70 HII regions located in the spiral galaxies NGC 1232, NGC 1365, NGC 2903, NGC 2997 and NGC 5236. These data are part of a project aiming at measuring the chemical abundances and characterizing the massive stellar content of metal-rich extragalactic HII regions. In this paper we describe our dataset, and present emission line fluxes for the whole sample. In 32 HII regions we measure at least one of the following auroral lines: [S II]4072, [N II]5755, [S III]6312 and [O II]7325. From these we derive electron temperatures, as well as oxygen, nitrogen and sulphur abundances, using classical empirical methods (both so-called "Te-based methods" and "strong line methods"). Under the assumption that the temperature gradient does not introduce severe biases, we find that the most metal-rich nebulae with detected auroral lines are found at 12+log(O/H)~8.9, i.e. about 60% larger than the adopted solar value. However, classical abundance determinations in metal-rich HII regions may be severely biased and must be tested with realistic photoionization models. The spectroscopic observations presented in this paper will serve as a homogeneous and high-quality database for such purpose.
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- ID:
- ivo://CDS.VizieR/J/AJ/116/2246
- Title:
- HII regions in UGCA 86, 92, 105 and UGC 4115
- Short Name:
- J/AJ/116/2246
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Luminosity functions in H{alpha} have been measured for H II regions in the four dwarf galaxies UGCA 86, UGCA 92, UGCA 105, and UGC 4115 using both the traditional flux measurement method of fixed-threshold photometry (FTP) and the new method, percentage-of-peak photometry (PPP). The UGCA galaxies are members of the IC 342-Maffei 1 group. These two methods give significantly different results in galaxies in which significant numbers of peaks are associated with H II region complexes. The work demonstrates that fluxes from FTP can lead to biased luminosity functions and that PPP should, in general, be preferred. It is also shown that PPP luminosity functions are not very sensitive to atmospheric transparency, whereas those constructed from FTP can be, based on data taken under different atmospheric conditions. Results to date for six galaxies show that spirals and dwarfs have luminosity functions of similar shape, which implies that the distribution of the masses of star formation sites is largely independent of the mass, and by implication, the metallicity, of the host galaxy. As measured by PPP, the mean surface brightness of the lower luminosity H II regions grows as the one-third power of the flux grows, exactly as predicted for an ensemble in which the gas density does not vary systematically with the mass of the star cluster. For the brightest H II regions, however, the relation steepens, which implies that the most massive star clusters are formed out of the densest clouds.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A38
- Title:
- Hints for a bar in M31 kinematics and morphology
- Short Name:
- J/A+A/611/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As the nearest large spiral galaxy, M 31 provides a unique opportunity to study the structure and evolutionary history of this galaxy type in great detail. Among the many observing programs aimed at M 31 are microlensing studies, which require good three-dimensional models of the stellar mass distribution. Possible non-axisymmetric structures like a bar need to be taken into account. Due to M 31's high inclination, the bar is difficult to detect in photometry alone. Therefore, detailed kinematic measurements are needed to constrain the possible existence and position of a bar in M 31. We obtained ~=220 separate fields with the optical integral-field unit spectrograph VIRUS-W, covering the whole bulge region of M 31 and parts of the disk. We derived stellar line-of-sight velocity distributions from the stellar absorption lines, as well as velocity distributions and line fluxes of the emission lines H{beta}, [OIII] and [NI]. Our data supersede any previous study in terms of spatial coverage and spectral resolution. We find several features that are indicative of a bar in the kinematics of the stars, we see intermediate plateaus in the velocity and the velocity dispersion, and correlation between the higher moment h3 and the velocity. The gas kinematics is highly irregular, but is consistent with non-triaxial streaming motions caused by a bar. The morphology of the gas shows a spiral pattern, with seemingly lower inclination than the stellar disk. We also look at the ionization mechanisms of the gas, which happens mostly through shocks and not through starbursts.
- ID:
- ivo://CDS.VizieR/J/AJ/113/905
- Title:
- HI observations of galaxies
- Short Name:
- J/AJ/113/905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present H I 21-cm line observations of 543 galaxies at low galactic latitude in the Galactic Anticenter region of the Zone of Avoidance (4h<={alpha}<=8h, 0{deg}=<{delta}=<37{deg}). The sample comprises 147 catalogued objects (from UGC, CGCG, MCG, and IRAS) still missing a redshift measurement and a list of 369 objects selected from an extensive optical compilation of galaxy candidates in this area. The spectra were acquired using the 305-m Arecibo telescope and cover a velocity range from -350 to +13800km/s at a resolution of about 16km/s. 196 galaxies were detected,59 of the catalogued ones and 137 from the optical compilation. The H I derived properties are presented, as is a discussion regarding the redshift distribution in this region. Our data seem to be consistent with a link across the Zone of Avoidance between the Pisces-Perseus supercluster and Abell 569.
- ID:
- ivo://CDS.VizieR/VIII/73
- Title:
- HI Parkes All Sky Survey Catalogue (HIPASS)
- Short Name:
- VIII/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The HI Parkes All-Sky Survey (HIPASS) Catalogue forms the largest uniform catalogue of HI sources compiled to date, with 4315 sources identified purely by their HI content. The catalogue data comprise the southern region DE<+2{deg} of HIPASS, the first blind HI survey to cover the entire southern sky. RMS noise for this survey is 13mJy/beam and the velocity range is -1280 to 12700km/s. Data search, verification and parametrization methods are discussed along with a description of measured quantities. Full catalogue data is made available to the astronomical community including positions, velocities, velocity widths, integrated fluxes and peak flux densities. Also available are on-sky moment maps, position- velocity moment maps and spectra of catalogue sources. A number of local large-scale features are observed in the space distribution of sources including the Super-Galactic plane and the Local Void. Notably, large-scale structure is seen at low Galactic latitudes, a region normally obscured at optical wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A116
- Title:
- HI4PI spectra and column density maps
- Short Name:
- J/A+A/594/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurement of the Galactic neutral atomic hydrogen (HI) column density, NHI, and brightness temperatures, Tb, is of high scientific value for a broad range of astrophysical disciplines. In the past two decades, one of the most-used legacy HI datasets has been the Leiden/Argentine/Bonn Survey (LAB). We release the HI 4-pi survey (HI4PI), an all-sky database of Galactic HI, which supersedes the LAB survey. The HI4PI survey is based on data from the recently completed first coverage of the Effelsberg-Bonn HI Survey (EBHIS) and from the third revision of the Galactic All-Sky Survey (GASS). EBHIS and GASS share similar angular resolution and match well in sensitivity. Combining both, they are ideally suited to be a successor to LAB. The new HI4PI survey outperforms the LAB in angular resolution (16.1', FWHM) and sensitivity (43mK RMS). Moreover, it has full spatial sampling and thus overcomes a major issue of LAB, which severely undersamples the sky. We publish all-sky column density maps of the neutral atomic hydrogen in the Milky Way, along with full spectroscopic data, in several map projections including HEALPix.
- ID:
- ivo://CDS.VizieR/J/AN/341/908
- Title:
- 308 Hipparcos stars EW Li and spectra
- Short Name:
- J/AN/341/908
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since early 2015 a spectroscopic monitoring campaign of selected Hipparcos stars is going on at the University Observatory Jena. The aim of this project is to search for lithium at 6708{AA}, which is a youth indicator, and to measure its equivalent width to identify young runaway stars in the sample (age<=50Myr) along with the Gaia data.
- ID:
- ivo://CDS.VizieR/J/AJ/159/197
- Title:
- HIRES radial velocities of HD9446, HD43691 & HD179079
- Short Name:
- J/AJ/159/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transit Ephemeris Refinement and Monitoring Survey is a project that aims to detect transits of intermediate-long period planets by refining orbital parameters of the known radial velocity planets using additional data from ground-based telescopes, calculating a revised transit ephemeris for the planet, then monitoring the planet host star during the predicted transit window. Here we present the results from three systems that had high probabilities of transiting planets: HD9446b and c, HD43691b, and HD179079b. We provide new radial velocity (RV) measurements that are then used to improve the orbital solution for the known planets. We search the RV data for indications of additional planets in orbit and find that HD9446 shows a strong linear trend of 4.8{sigma}. Using the newly refined planet orbital solutions, which include a new best-fit solution for the orbital period of HD9446c, and an improved transit ephemerides, we found no evidence of transiting planets in the photometry for each system. Transits of HD9446b can be ruled out completely and transits HD9446c and HD43691b can be ruled out for impact parameters up to b=0.5778 and b=0.898, respectively, due to gaps in the photometry. A transit of HD179079b cannot be ruled out, however, due to the relatively small size of this planet compared to the large star and thus low signal to noise. We determine properties of the three host stars through spectroscopic analysis and find through photometric analysis that HD9446 exhibits periodic variability.
- ID:
- ivo://CDS.VizieR/J/AJ/162/89
- Title:
- HIRES radial velocity follow up for Kepler-129
- Short Name:
- J/AJ/162/89
- Date:
- 14 Mar 2022 06:24:52
- Publisher:
- CDS
- Description:
- We present the discovery of Kepler-129d (P_d_=7.2_-0.3_^+0.4^yr, m_sini_d__=8.3_-0.7_^+1.1^M_Jup_, e_d_=0.15_-0.05_^+0.07^) based on six years of radial-velocity observations from Keck/HIRES. Kepler-129 also hosts two transiting sub-Neptunes: Kepler-129b (P_b_= 15.79days, r_b_=2.40{+/-}0.04R{Earth}) and Kepler-129c (P_c_=82.20days, r_c_=2.52{+/-}0.07R{Earth}) for which we measure masses of m_b_<20M{Earth} and m_c_=43_-12_^+13^M{Earth}. Kepler-129 is a hierarchical system consisting of two tightly packed inner planets and a massive external companion. In such a system, two inner planets precess around the orbital normal of the outer companion, causing their inclinations to oscillate with time. Based on an asteroseismic analysis of Kepler data, we find tentative evidence that Kepler-129b and c are misaligned with stellar spin axis by >~38{deg}, which could be torqued by Kepler-129 d if it is inclined by >~19{deg} relative to inner planets. Using N-body simulations, we provide additional constraints on the mutual inclination between Kepler-129d and inner planets by estimating the fraction of time during which two inner planets both transit. The probability that two planets both transit decreases as their misalignment with Kepler-129d increases. We also find a more massive Kepler-129c enables the two inner planets to become strongly coupled and more resistant to perturbations from Kepler-129d. The unusually high mass of Kepler-129c provides a valuable benchmark for both planetary dynamics and interior structure, since the best-fit mass is consistent with this 2.5R{Earth} planet having a rocky surface.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/270
- Title:
- HI-selected-Lyman limit system metallicities
- Short Name:
- J/ApJ/833/270
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measured metallicities for 33 z=3.4-4.2 absorption line systems drawn from a sample of HI-selected-Lyman limit systems (LLSs) identified in Sloan Digital Sky Survey (SDSS) quasar spectra and stratified based on metal line features. We obtained higher-resolution spectra with the Keck Echellette Spectrograph and Imager, selecting targets according to our stratification scheme in an effort to fully sample the LLS population metallicity distribution. We established a plausible range of HI column densities and measured column densities (or limits) for ions of carbon, silicon, and aluminum, finding ionization-corrected metallicities or upper limits. Interestingly, our ionization models were better constrained with enhanced {alpha}-to-aluminum abundances, with a median abundance ratio of [{alpha}/Al]=0.3. Measured metallicities were generally low, ranging from [M/H]=-3 to -1.68, with even lower metallicities likely for some systems with upper limits. Using survival statistics to incorporate limits, we constructed the cumulative distribution function (CDF) for LLS metallicities. Recent models of galaxy evolution propose that galaxies replenish their gas from the low-metallicity intergalactic medium (IGM) via high-density HI "flows" and eject enriched interstellar gas via outflows. Thus, there has been some expectation that LLSs at the peak of cosmic star formation (z~3) might have a bimodal metallicity distribution. We modeled our CDF as a mix of two Gaussian distributions, one reflecting the metallicity of the IGM and the other representative of the interstellar medium of star-forming galaxies. This bimodal distribution yielded a poor fit. A single Gaussian distribution better represented the sample with a low mean metallicity of [M/H]~-2.5.
