- ID:
- ivo://CDS.VizieR/J/ApJS/172/523
- Title:
- COSMOS field Ly{alpha} emitters at z~5.7
- Short Name:
- J/ApJS/172/523
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a narrow-band optical survey of a contiguous area of 1.95deg^2^, covered by the Cosmic Evolution Survey (COSMOS). Both optical narrow-band ({lambda}c=8150{AA} and {delta}{lambda}=120{AA}) and broad-band (B, V, g', r', i', and z') imaging observations were performed with the Subaru prime-focus camera, Suprime-Cam on the Subaru Telescope. We provide the largest contiguous narrow-band survey, targeting Ly{alpha} emitters (LAEs) at z~5.7. We find a total of 119 LAE candidates at z~5.7. Over the wide-area covered by this survey, we find no strong evidence for large-scale clustering of LAEs. We estimate a star formation rate (SFR) density of ~7x10-4M_{sun}_/yr/Mpc^3^ for LAEs at z~5.7 and compare it with previous measurements.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/310/893
- Title:
- C_2_ Phillips and CN Red bands in HD 56126
- Short Name:
- J/A+A/310/893
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the detection of molecular absorption lines in the optical spectrum of the post-AGB star HD 56126. The C_2_ Phillips A^1^{PI}_u_-X^1^{SIGMA}^+^_g_(1,0), (2,0), and (3,0); Swan d^3^{PI}_g_-a^3^{PI}_u_(0,0) and (1,0); and CN Red system A^2^{PI}-X^2^{SIGMA}^+^ (1,0), (2,0), (3,0), and (4,0) bands have been identified. From the identification of the molecular bands we find an expansion velocity of 8.5+/-0.6km/s independent of excitation condition or molecular specie. On the basis of the expansion velocity, rotational temperatures, and molecular column densities we argue that the line-forming region is the AGB remnant. This is in agreement with the expansion velocity derived from the CO lines. We find column densities of logN_C_2__=15.3+/-0.3cm^-2^ and logN_CN_=15.5+/-0.3cm^-2^, and rotational temperatures of T_rot_=242+/-20K and T_rot_=24+/-5K respectively for C_2_ and CN. By studying molecular line absorption in optical spectra of post-AGB stars we have found a new tracer of the AGB remnant. From comparison with the results of CO and IR observations it is possible to obtain information on non-spherical behavior of the AGB remnant. Using different molecules with different excitation conditions it should be possible to study the AGB remnant as a function of the distance to the star, and thus as a function of the evolutionary status of the star on the AGB.
243. CP stars
- ID:
- ivo://CDS.VizieR/J/A+AS/107/353
- Title:
- CP stars
- Short Name:
- J/A+AS/107/353
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Fine analyses of the silicon star HD 43819 and the CP star HD 147550 are presented using ATLAS9 model atmospheres whose predictions fit the optical region spectrophotometry and H{gamma} profiles and have the same bulk metallicity as the deduced abundances. For HD 43819 except for scandium and nickel, the derived abundances of the iron peak elements are around 10 times solar while those of the rare earths are about 1000 times solar. The lighter elements are generally underabundant except for silicon and calcium which are overabundant. HD 147550 is helium and calcium poor; carbon, magnesium, aluminum, scandium, titanium, and iron normal; and sulfur, chromium, manganese, nickel, strontium, zirconium, barium, europium, and mercury rich. It is a nonmagnetic CP star intermediate between the HgMn and the hot Am stars.
- ID:
- ivo://CDS.VizieR/J/A+A/607/A91
- Title:
- CS 29497-004 abundances
- Short Name:
- J/A+A/607/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report an abundance analysis for the highly r-process-enhanced (r-II) star CS 29497-004, a very metal-poor giant with solar system Teff=5013K and [Fe/H]=-2.85, whose nature was initially discovered in the course of the HERES project. Our analysis is based on high signal-to-noise ratio, high-resolution (R~75000) VLT/UVES spectra and MARCS model atmospheres under the assumption of local thermodynamic equilibrium, and obtains abundance measurements for a total of 46 elements, 31 of which are neutron-capture elements. As is the case for the other ~25 r-II stars currently known, the heavy-element abundance pattern of CS 29497-004 well-matches a scaled solar system second peak r-process-element abundance pattern. We confirm our previous detection of Th, and demonstrate that this star does not exhibit an "actinide boost". Uranium is also detected (log{epsilon}(U)=-2.20+/-0.30), albeit with a large measurement error that hampers its use as a precision cosmochronometer. Combining the various elemental chronometer pairs that are available for this star, we derive a mean age of 12.2+/-3.7Gyr using the theoretical production ratios from published waiting-point approximation models. We further explore the high-entropy wind model (Farouqi et al., 2010ApJ...712.1359F) production ratios arising from different neutron richness of the ejecta (Ye), and derive an age of 13.7+/-4.4Gyr for a best-fitting Ye=0.447. The U/Th nuclei-chronometer is confirmed to be the most resilient to theoretical production ratios and yields an age of 16.5+/-6.6Gyr. Lead (Pb) is also tentatively detected in CS 29497-004, at a level compatible with a scaled solar r-process, or with the theoretical expectations for a pure r-process in this star.
245. C stars in SMC
- ID:
- ivo://CDS.VizieR/J/A+AS/97/603
- Title:
- C stars in SMC
- Short Name:
- J/A+AS/97/603
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate positions and charts for 1707 carbon stars in the Small Magellanic Cloud identified on GRISM plates are presented. The catalog provides data on magnitudes, colors, and carbon-abundance measurements and can be used for selecting carbon stars with special characteristics.
- ID:
- ivo://CDS.VizieR/J/MNRAS/359/930
- Title:
- CUYS survey of Ha+NII ELG galaxies
- Short Name:
- J/MNRAS/359/930
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the CIDAUCMYale (Centro de Investigaciones de Astronomia, Universidad Complutense de Madrid, and Yale University) Survey (CUYS) for H{alpha}+[NII] 6549, 6584{AA} emission-line galaxies (ELGs) using objective-prism spectra. The most important properties of a catalogue with 427 entries and significant subsets are analysed. The complete sample contains 183 statistically confirmed ELGs in a sky area of 151deg^2^ and redshift up to 0.14. We determine the parameters of the H{alpha} luminosity function using the H{alpha}+[NII] flux directly measured on the ELG spectra in this sample, and the star formation rate density derived is in agreement with values reported in the literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/636/610
- Title:
- Damped Ly{alpha} systems at z<1.65
- Short Name:
- J/ApJ/636/610
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of our Hubble Space Telescope Cycle 11 survey for low-redshift (z<1.65) damped Ly{alpha} (DLA) systems in the UV spectra of quasars selected from the Sloan Digital Sky Survey (SDSS) Early Data Release (Cat. <J/AJ/123/567>). These quasars have strong intervening MgII-FeII systems that are known signatures of high column density neutral gas. In total, including our previous surveys, UV observations of Ly{alpha} absorption in 197 MgII systems with z<1.65 and rest equivalent width (REW) W_0_^{lambda}2796^>=0.3{AA} have now been obtained.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/998
- Title:
- Damped Lyman{alpha} systems
- Short Name:
- J/MNRAS/392/998
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a sample of 21 damped Lyman alpha systems (DLAs) and 35 sub-DLAs, we evaluate the D-index=[EW({AA})/{Delta}v(km/s)]x1000 from high-resolution spectra of the MgII {lambda}2796 profile. This sample represents an increase in the sub-DLA statistics by a factor of 4 over the original D-index sample. We investigate various techniques to define the velocity spread ({Delta}v) of the MgII line to determine an optimal D-index for the identification of DLAs. The success rate of DLA identification is 50-55 per cent, depending on the velocity limits used, improving by a few per cent when the column density of FeII is included in the D-index calculation. We recommend the set of parameters that are judged to be most robust, have a combination of high DLA identification rate (57 per cent) and low DLA miss rate (6 per cent) and most cleanly separate the DLAs and sub-DLAs (Kolmogorov-Smirnov probability 0.5 per cent). These statistics demonstrate that the D-index is the most efficient technique for selecting low-redshift DLA candidates.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/3428
- Title:
- Damped Lyman Alpha systems equivalent width
- Short Name:
- J/MNRAS/471/3428
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the statistical properties of neutral gas at redshifts 0.11<z<1.65 from ultraviolet (UV) measurements of quasar Ly{alpha} absorption lines corresponding to 369 MgII systems with W{lambda}2796_0_>=0.3{AA}. In addition to the 41 damped Lyman alpha (DLA) systems presented in Rao et al. (2006ApJ...636..610R, Cat. J/ApJ/636/610), the current DLA sample includes 29 newly discovered DLAs. Formally, this DLA sample includes 70 systems with N_HI_>=2*10^20^atoms/cm^2^. We find that the incidence of DLAs, or the product of their gas cross-section and their comoving number density, can be described by n_DLA_(z)=(0.027+/-0.007)(1+z)^(1.682+/-0.200)^ over the redshift range of 0<z<5. The cosmic mass density of neutral gas can be described by {Omega}_DLA_(z)=(4.77+/-1.60)x10^-4^(1+z)^(0.64+/-0.27)^. The low-redshift column density distribution function is well fitted by a power law of the form f(N)~N^{beta}^ with {beta}=-1.46+/-0.20. It is consistent with the high redshift as well as z=0 estimates at the high-column density end but lies between them at the low-column density end. We discuss possible N_HI_ and metallicity bias in Mg II-selected DLA samples and show that such biases do not exist in the current data at z<1.65. Thus, at least at z<1.65, DLAs found through MgII selection statistically represent the true population of DLAs. However, we caution that studies of DLA metallicities should take into account the relative incidence of DLAs with respect to W_0_{lambda}2796^ (or gas velocity spread) in order to
- ID:
- ivo://CDS.VizieR/J/ApJ/688/597
- Title:
- Debris disks in NGC 2232
- Short Name:
- J/ApJ/688/597
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe Spitzer IRAC and MIPS observations of the nearby 25Myr old open cluster NGC 2232. Combining these data with ROSAT All-Sky Survey observations, proper motions, and optical photometry/spectroscopy, we construct a list of highly probable cluster members. We identify one A-type star, HD 45435, that has definite excess emission at 4.5-24um indicative of debris from terrestrial planet formation. We also identify 2-4 late-type stars with possible 8um excesses and 8 early-type stars with definite 24um excesses. Constraints on the dust luminosity and temperature suggest that the detected excesses are produced by debris disks. From our sample of B and A stars, stellar rotation appears to be correlated with 24um excess, a result that would be expected if massive primordial disks evolve into massive debris disks. To explore the evolution of the frequency and magnitude of debris around A-type stars, we combine our results with data for other young clusters.
