- ID:
- ivo://CDS.VizieR/J/ApJ/741/98
- Title:
- Spectroscopy of galaxy clusters to find LCBGs
- Short Name:
- J/ApJ/741/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the DEIMOS spectrograph on the Keck II Telescope to obtain spectra of galaxies in the fields of five distant, rich galaxy clusters over the redshift range 0.5<z<0.9 in a search for luminous compact blue galaxies (LCBGs). Unlike traditional studies of galaxy clusters, we preferentially targeted blue cluster members identified via multi-band photometric pre-selection based on imaging data from the WIYN telescope. Of the 1288 sources that we targeted, we determined secure spectroscopic redshifts for 848 sources, yielding a total success rate of 66%. Our redshift measurements are in good agreement with those previously reported in the literature, except for 11 targets which we believe were previously in error. Within our sample, we confirm the presence of 53 LCBGs in the five galaxy clusters.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/613/A56
- Title:
- Spectroscopy of globular clusters
- Short Name:
- J/A+A/613/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new abundance measurements for eleven GCs in the Local Group galaxies NGC 147, NGC 6822, and Messier 33. These are combined with previously published observations of four GCs in the Fornax and WLM galaxies. The abundances were determined from analysis of integrated-light spectra, obtained with HIRES on the Keck I telescope and with UVES on the VLT. We find that the clusters with [Fe/H]<-1.5 are all alpha-enhanced at about the same level as Milky Way GCs. Their Na abundances are also generally enhanced relative to Milky Way halo stars, suggesting that these extragalactic GCs resemble their Milky Way counterparts in containing significant fractions of Na-rich stars. For [Fe/H]>-1.5, the GCs in M33 are also alpha-enhanced, while the GCs that belong to dwarfs (NGC 6822 SC7 and Fornax 4) have closer to Solar-scaled alpha-element abundances. The abundance patterns in SC7 are remarkably similar to those in the Galactic GC Ruprecht 106, including significantly sub-solar [Na/Fe] and [Ni/Fe] ratios. In NGC 147, the GCs with [Fe/H]<-2.0 account for about 6% of the total luminosity of stars in the same metallicity range, a lower fraction than those previously found in the Fornax and WLM galaxies, but substantially higher than in the Milky Way halo.
- ID:
- ivo://CDS.VizieR/J/A+A/601/A96
- Title:
- Spectroscopy of globular clusters
- Short Name:
- J/A+A/601/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We test the performance of our analysis technique for integrated-light spectra by applying it to seven well-studied Galactic GCs that span a wide range of metallicities. Integrated-light spectra were obtained by scanning the slit of the UVES spectrograph on the ESO Very Large Telescope across the half-light diameters of the clusters. We modelled the spectra using resolved Hubble Space Telescope colour-magnitude diagrams (CMDs), as well as theoretical isochrones, in combination with standard stellar atmosphere and spectral synthesis codes. The abundances of Fe, Na, Mg, Ca, Ti, Cr, and Ba were compared with literature data for individual stars in the clusters. The typical differences between iron abundances derived from our integrated-light spectra and those compiled from the literature are less than 0.1 dex. A larger difference is found for one cluster (NGC 6752), and is most likely caused primarily by stochastic fluctuations in the numbers of bright red giants within the scanned area. As expected, the alpha-elements (Ca, Ti) are enhanced by about 0.3 dex compared to the Solar-scaled composition, while the [Cr/Fe] ratios are close to Solar. When using up-to-date line lists, our [Mg/Fe] ratios also agree well with literature data. Our [Na/Fe] ratios are, on average, 0.08-0.14 dex lower than average values quoted in the literature, and our [Ba/Fe] ratios may be overestimated by 0.20-0.35 dex at the lowest metallicities. We find that analyses based on theoretical isochrones give very similar results to those based on resolved CMDs. Overall, the agreement between our integrated-light abundance measurements and the literature data is satisfactory. Refinements of the modelling procedure, such as corrections for stellar evolutionary and non-LTE effects, might further reduce some of the remaining offsets.
- ID:
- ivo://CDS.VizieR/J/ApJ/708/1335
- Title:
- Spectroscopy of globulars in NGC 5128
- Short Name:
- J/ApJ/708/1335
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new integrated light spectroscopy of globular clusters (GCs) in NGC 5128, a nearby giant elliptical galaxy less than 4Mpc away, in order to measure radial velocities and derive ages, metallicities, and alpha-element abundance ratios. Using the Gemini South 8 meter telescope with the instrument Gemini Multi-Object Spectrograph, we obtained spectroscopy in the range of ~3400-5700{AA} for 72 GCs with a signal-to-noise ratio greater than 30{AA}^-1^; and we have also discovered 35 new GCs within NGC 5128 from our radial velocity measurements. We measured and compared the Lick indices from H{delta}_A_ through Fe5406 with the single stellar population models of Thomas et al. (2003MNRAS.339..897T, 2004MNRAS.351L..19T) in order to derive age, metallicity, and [{alpha}/Fe] values.
- ID:
- ivo://CDS.VizieR/J/ApJ/892/137
- Title:
- Spectroscopy of Grus II, Tuc IV and Tuc V
- Short Name:
- J/ApJ/892/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Magellan/IMACS spectroscopy of three recently discovered ultra-faint Milky Way satellites, Grus II, Tucana IV, and Tucana V. We measure systemic velocities of v_hel_=-110.0+/-0.5km/s, v_hel_=15.9_-1.7_^+1.8^km/s, and v_hel_=-36.2_-2.2_^+2.5^km/s for the three objects, respectively. Their large relative velocities demonstrate that the satellites are unrelated despite their close physical proximity. We determine a velocity dispersion for Tuc IV of {sigma}=4.3_-1.0_^+1.7^km/s, but we cannot resolve the velocity dispersions of the other two systems. For Gru II, we place an upper limit (90% confidence) on the dispersion of {sigma}<1.9km/s, and for Tuc V, we do not obtain any useful limits. All three satellites have metallicities below [Fe/H]=-2.1, but none has a detectable metallicity spread. We determine proper motions for each satellite based on Gaia astrometry and compute their orbits around the Milky Way. Gru II is on a tightly bound orbit with a pericenter of 25_-7_^+6^kpc and orbital eccentricity of 0.45_-0.05_^+0.08^. Tuc V likely has an apocenter beyond 100kpc and could be approaching the Milky Way for the first time. The current orbit of Tuc IV is similar to that of Gru II, with a pericenter of 25_-8_^+11^kpc and an eccentricity of 0.36_-0.06_^+0.13^. However, a backward integration of the position of Tuc IV demonstrates that it collided with the Large Magellanic Cloud at an impact parameter of 4kpc ~120Myr ago, deflecting its trajectory and possibly altering its internal kinematics. Based on their sizes, masses, and metallicities, we classify Gru II and Tuc IV as likely dwarf galaxies, but the nature of Tuc V remains uncertain.
- ID:
- ivo://CDS.VizieR/J/PAZh/25/18
- Title:
- Spectroscopy of H{alpha} blue stars in M 33
- Short Name:
- J/PAZh/25/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Multiobject spectroscopy for 118 blue stars with an H{alpha} excess in the galaxy M 33 from the lists of SS 433 and LBV candidates and other rare types of massive stars is presented. The H{alpha} parameters and the relative intensities of the [NII]6584{AA} and [SII]6716{AA} lines are given. We identified stars with a broad H{alpha} emission line, which is probably emitted in the stellar wind.
2557. Spectroscopy of HD 45166
- ID:
- ivo://CDS.VizieR/J/A+A/444/895
- Title:
- Spectroscopy of HD 45166
- Short Name:
- J/A+A/444/895
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The binary star HD 45166 has been observed since 1922 but its orbital period has not yet been found. It is considered a peculiar Wolf-Rayet star, and its assigned classification has varied. For this reason we included the object as a candidate V Sge star and performed spectroscopy in order to search for its putative orbital period. High-resolution spectroscopic observations show that the spectrum, in emission and in absorption, is quite rich. The emission lines have great diversity of widths and profiles. The full widths at half maximum vary from 70km/s for the weakest lines up to 370km/s for the most intense ones. The Hydrogen and Helium lines are systematically broader than the CNO lines. Assuming that HD 45166 is a double-line spectroscopic binary, it present s an orbital period of P=1.596+/-0.003-day, with an eccentricity of e=0.18+/-0.08. In addition, a search for periodicity using standard techniques reveals that the emission lines present at least two other periods, of 5 and 5 hour. The secondary star has a spectral type of B7 V and, therefore, should have a mass of about M=4.8M_{sun}_. Given the radial velocity amplitudes, we determined the mass of the hot (primary) star as M=4.2+/-0.7M_{sun}_ and the inclination angle of the system, i=0.77+/-0.09deg. As the eccentricity of the orbit is non zero, the Roche lobes increase and decrease as a function of the orbital phase. At periastron, the secondary star fills its Roche lobe. The distance to the star has been re-determined as d=1.3+/-0.2kpc and a color excess of E(B-V)=0.155+/-0.007 has been derived. This implies an absolute B magnitude of -0.6 for the primary star and -0.7 for the B7 star. We suggest that the discrete absorption components (DACs) observed in the ultraviolet with a periodicity similar to the orbital period may be induced by periastron events.
2558. Spectroscopy of HD 86222
- ID:
- ivo://CDS.VizieR/J/A+A/564/A26
- Title:
- Spectroscopy of HD 86222
- Short Name:
- J/A+A/564/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic and photometric analysis of the quintuple star HD 86222 with an eclipsing component. Until now three visual components A, B, and C of this multiple star were known. Four components in the A/B pair were detected during the examination of the cross correlation functions obtained from the spectra.
- ID:
- ivo://CDS.VizieR/J/A+AS/124/441
- Title:
- Spectroscopy of HD 45677 = MWC 142
- Short Name:
- J/A+AS/124/441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength regions 3750-5112 and 7065-10212{AA} of the spectrum of HD 45677. Over 235 features are identified and a comparison of our results with those of other authors is provided. We also discuss the variability of the lines using equivalent widths and the line spectrum. We conclude that the gaseous shell surrounding the star has a temperature of the order of 7000K and that its distance to the star is less than ten stellar radii. We discuss the similarity of this star to other stars previously analyzed.
- ID:
- ivo://CDS.VizieR/J/A+AS/117/281
- Title:
- Spectroscopy of HD 51585 (= OY Gem)
- Short Name:
- J/A+AS/117/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse CCD spectroscopic material obtained at the Haute Provence Observatory between 1990 and 1993, covering the wavelength region 380-1100mm. 320 emission lines were measured and identified. Of these about 40% correspond to permitted or forbidden lines of ionized iron. Many forbidden lines (20% of the total) are present, including many classic nebular lines. We also provide a comparison of our results with those of other authors. The equivalent width measurements permit to follow in detail the variations of the lines of several elements over the three years and to compare them to variations reported by other authors. On our material the largest variations correspond to helium, which varied by a factor of two and are not in phase with the variations of hydrogen. Many helium lines exhibit P Cyg type profiles, indicating strong outflow of matter from the star. The lines of other elements follow either the variations of the helium or of the hydrogen lines. The radial velocity varies over the years, with an amplitude of more than 60km/s.
