- ID:
- ivo://CDS.VizieR/J/MNRAS/440/2265
- Title:
- Spectroscopy of NGC3310 HII regions
- Short Name:
- J/MNRAS/440/2265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Numerical simulations of minor mergers predict little enhancement in the global star formation activity. However, it is still unclear the impact they have on the chemical state of the whole galaxy and on the mass build-up in the galaxy bulge and disc. We present a two-dimensional analysis of NCG 3310, currently undergoing an intense starburst likely caused by a recent minor interaction, using data from the PPAK Integral Field Spectroscopy Nearby Galaxies Survey (PINGS). With data from a large sample of about a hundred HII regions identified throughout the disc and spiral arms, we derive, using strong-line metallicity indicators and direct derivations, a rather flat gaseous abundance gradient. Thus, metal mixing processes occurred, as in observed galaxy interactions. Spectra from PINGS data and additional multiwavelength imaging were used to perform a spectral energy distribution fitting to the stellar emission and a photoionization modelling of the nebulae. The ionizing stellar population is characterized by single populations with a narrow age range (2.5-5Myr) and a broad range of masses (10^4^-6x10^6^M_{sun}_). The effect of dust grains in the nebulae is important, indicating that 25-70% of the ultraviolet photons can be absorbed by dust. The ionizing stellar population within the Hii regions represents typically a few per cent of the total stellar mass. This ratio, a proxy to the specific star formation rate, presents a flat or negative radial gradient. Therefore, minor interactions may indeed play an important role in the mass build-up of the bulge.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/123/2828
- Title:
- Spectroscopy of northern NLTT stars
- Short Name:
- J/AJ/123/2828
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results of an all-sky search for late-type dwarfs within 20pc of the Sun using the New Luyten Two-Tenths (NLTT) catalog cross-referenced with the Two Micron All Sky Survey (2MASS) database. The results were obtained with low-resolution optical spectroscopic follow-up of candidate nearby stars as a preliminary test of our methodology. M_J_, derived using spectral indices, and 2MASS J are used to estimate distances. Out of the 70 objects observed, 28 are identified as previously unrecognized objects within 25pc of the Sun, and up to 19 of these are within 20pc. One, LP 647-13, is an M9-type dwarf at 10.5pc, making it one of the four closest M9 dwarfs currently known. We also discuss the chromospheric activity of the observed dwarfs.
- ID:
- ivo://CDS.VizieR/J/ApJ/782/8
- Title:
- Spectroscopy of 104 objects in the ONC
- Short Name:
- J/ApJ/782/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed low-resolution (R~40) near-infrared (0.9-2.4{mu}m) multi-object spectroscopy of 240 isolated point sources having apparent H-band magnitudes between 9 and 18 in the central 5'x6' of the Orion Trapezium cluster. The observations were performed over four nights at the Canada-France-Hawaii Telescope using the visiting instrument SIMON, an infrared imager and multi-object spectrograph. We present the spectra of 104 objects with accurately derived spectral types including 7 new objects having masses below the hydrogen-burning limit, and 6 objects with masses below the deuterium-burning limit. The spectral classification is performed by fitting previously classified spectral templates of dwarf stars (K4-M3) and optically classified young stellar and substellar objects (M4-L0), to the entire 0.9-2.4{mu}m spectral energy distribution in order to assign a spectral type and visual extinction for each object. Of the 104 objects studied, 44 have been previously classified spectroscopically using various techniques. We perform a rigorous comparison between the previous classifications and our own and find them to be in good agreement. Using the dereddened H-band magnitudes, the classified objects are used to create an Hertzsprung-Russell diagram for the cluster. We find that the previous age estimates of ~1Myr to be consistent with our results. Consistent with previous studies, numerous objects are observed to have luminosities several magnitudes above the 1Myr isochrone. Numerous objects exhibiting emission features in the J band are also reported.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/1536
- Title:
- Spectroscopy of of IC4499 red giants
- Short Name:
- J/MNRAS/411/1536
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocity and metallicity measurements for the far southern Galactic globular cluster IC 4499. We selected several hundred target red giant stars in and around the cluster from the 2MASS point source catalogue, and obtained spectra at the near-infrared calcium triplet using the AAOmega spectrograph. Observations of giants in globular clusters M4, M22 and M68 were taken to provide radial velocity and metallicity comparison objects.
- ID:
- ivo://CDS.VizieR/J/AJ/136/181
- Title:
- Spectroscopy of PC 1643+4631A,B
- Short Name:
- J/AJ/136/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first measurement and detection of coherence in the intergalactic medium (IGM) at substantially high redshift (z~3.8) and on large physical scales (~2.5h^-1^_70_Mpc). We perform the measurement by presenting new observations of the high-redshift quasar pair PC 1643+4631A, B and their Ly{alpha}-absorber coincidences. With data collected from Keck I Low Resolution Imaging Spectrometer (LRIS) in a 10200s integration, we have full coverage of the Ly{alpha} forest over the redshift range 2.6<z<3.8 at a resolution of 3.6{AA} (~220km/s).
- ID:
- ivo://CDS.VizieR/J/A+A/574/A109
- Title:
- Spectroscopy of Planetary Nebulae in NGC 5128
- Short Name:
- J/A+A/574/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Planetary nebulae (PNe) are excellent tracers of the common low mass stars through their strong and narrow emission lines. The velocities of large numbers of PNe are excellent tracers of galaxy kinematics. NGC 5128, the nearest large early-type galaxy offers the possibility to gather a large PN sample. Imaging and spectroscopic observations of PNe in NGC 5128 were obtained to find PNe and measure their velocities. Combined with literature data, a large sample of high quality kinematic probes is assembled for dynamical studies in NGC 5128. NTT Imaging was obtained in 15 fields in NGC 5128 over 1 degree with EMMI and [OIII] and off-band filters. Newly detected emission sources, combined with literature PN, were used as input for FLAMES multi-fibre spectroscopy in MEDUSA mode. Spectra of the 4600-5100{AA} region were analysed and velocities were measured based on [OIII]4959,5007{AA} and often H{beta}. The chief results are catalogues of 1118 PN candidates and 1267 spectroscopically confirmed PNe in NGC 5128. The catalogue of PN candidates contains 1060 potential PNe discovered with NTT EMMI imaging and 58 from literature surveys. The spectroscopically confirmed PN catalogue has FLAMES radial velocity and emission line measurements for 1135 PNe, of which 486 are newly confirmed here. An additional 132 PN radial velocities are available from the literature. For 629 PNe observed with FLAMES, H-beta was measured in addition to the [OIII] emission lines. Nine targets show double-lined or more complex profiles (19 components in total), and their possible origin is discussed. FLAMES spectra of 48 globular clusters were also targetted, and 11 had emission lines detected (two with multiple components), but only 3 are PNe likely to belong to the host globular. Conclusions. The total of 1267 confirmed PNe in NGC 5128 with radial velocity measurements, of which 1135 have small velocity errors, is the largest such collection of individual kinematic probes in an early-type galaxy. This PN dataset, as well as the catalogue of 1118 PN candidates, are valuable resources for detailed investigation of the kinematics and stellar population of NGC 5128.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A12
- Title:
- Spectroscopy of 1,2-propanediol
- Short Name:
- J/A+A/570/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ethandiol is among the largest complex organic molecules detected in space thus far. It has been found in different types of molecular clouds. The two propanediol isomers are the next larger diols. Hence,they are viable candidates to be searched for in space. We want to provide sufficiently large and accurate sets of spectroscopic parameters of 1,2-propanediol to facilitate searches for this molecule at millimeter and longer submillimeter wavelengths. We recorded rotational spectra of 1,2-propanediol in three large frequency windows between 38 and 400GHz. We made extensive assignments for the three lowest energy conformers to yield spectroscopic parameters up to eighth order. Our present data will be helpful for identifying 1,2-propanediol at moderate submillimeter or longer wavelengths with radio telescope arrays such as ALMA, NOEMA, or EVLA. In particular, its detection with ALMA in sources, in which ethanediol was detected, appears to be promising.
17478. Spectroscopy of QSO pairs
- ID:
- ivo://CDS.VizieR/J/ApJS/175/29
- Title:
- Spectroscopy of QSO pairs
- Short Name:
- J/ApJS/175/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Ly{alpha} forest has opened a new redshift regime for cosmological investigation. At z>2 it provides a unique probe of cosmic geometry and an independent constraint on dark energy that is not subject to standard candle or ruler assumptions. In Paper I of this series on using the Ly{alpha} forest observed in pairs of QSOs for a new application of the Alcock-Paczynski test, we present and discuss the results of a campaign to obtain moderate-resolution spectroscopy (FWHM~2.5{AA}) of the Ly{alpha} forest in pairs of QSOs with small redshift differences ({Delta}z<0.25, z>2.2) and arcminute separations ({Theta}<5'). This data set, composed of seven individual QSOs, 35 pairs, and one triplet, is also well suited for future investigations of the coherence of Ly{alpha} absorbers on ~1Mpc transverse scales and the transverse proximity effect. We note seven revisions for previously published QSO identifications and/or redshifts.
- ID:
- ivo://CDS.VizieR/J/ApJ/678/635
- Title:
- Spectroscopy of quasar binary candidates
- Short Name:
- J/ApJ/678/635
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopy of binary quasar candidates, with component separations of 3"<={Delta}{theta}<6", selected from SDSS DR4 using kernel density estimation (KDE). Of our 27 new quasar pair observations, 10 are binary quasars, which doubles the number of known g<21 binaries with 3"<={Delta}{theta}<6" separations. Several of our observed binaries are wide-separation lens candidates that merit additional higher resolution spectroscopy, as well as deep imaging to search for lensing galaxies. Our candidates are initially selected by UV excess (u-g<1), but are otherwise selected irrespective of the relative colors of the quasar pair, and we thus use them to suggest optimal color similarity and photometric redshift approaches for targeting binary quasars or projected quasar pairs. We find that a third or more of all binary quasars have quite dissimilar components on the basis of a typical color similarity criterion ({chi}^2^_color_<~20). From a sample that is complete on proper scales of 23.7h^-1^kpc<R_prop_<29.9h^-1^kpc, we determine the projected quasar correlation function.
- ID:
- ivo://CDS.VizieR/J/ApJ/902/17
- Title:
- Spectroscopy of quiescent gal. in 9 lensing clusters
- Short Name:
- J/ApJ/902/17
- Date:
- 03 Mar 2022 11:35:20
- Publisher:
- CDS
- Description:
- We measure the central stellar velocity dispersion function for quiescent galaxies in a set of nine northern clusters in the redshift range 0.18<z<0.29 and with strong lensing arcs in Hubble Space Telescope images. The velocity dispersion function links galaxies directly to their dark matter halos. From dense SDSS and MMT/Hectospec spectroscopy, we identify 222-463 spectroscopic members in each cluster. We derive physical properties of cluster members including redshift, D_n_4000, and central stellar velocity dispersion and we include a table of these measurements for 3419 cluster members. We construct the velocity dispersion functions for quiescent galaxies with D_n_4000>1.5 and within R200. The cluster velocity dispersion functions all show excesses at {sigma}>~250km/s compared to the field velocity dispersion function. The velocity dispersion function slope at large velocity dispersion ({sigma}>160km/s) is steeper for more massive clusters, consistent with the trend observed for cluster luminosity functions. The spatial distribution of galaxies with large velocity dispersion at radii larger than R200 further underscores the probable major role of dry mergers in the growth of massive cluster galaxies during cluster assembly.