- ID:
- ivo://CDS.VizieR/J/ApJ/818/30
- Title:
- Lag measurements for 15 z<0.8 QSOs from the SDSS-RM
- Short Name:
- J/ApJ/818/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Reverberation mapping (RM) measurements of broad-line region (BLR) lags in z>0.3 quasars are important for directly measuring black hole masses in these distant objects, but so far there have been limited attempts and success given the practical difficulties of RM in this regime. Here we report preliminary results of 15 BLR lag measurements from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, a dedicated RM program with multi-object spectroscopy designed for RM over a wide redshift range. The lags are based on the 2014 spectroscopic light curves alone (32 epochs over six months) and focus on the H{beta} and Mg II broad lines in the 100 lowest-redshift (z<0.8) quasars included in SDSS-RM; they represent a small subset of the lags that SDSS-RM (including 849 quasars to z~4.5) is expected to deliver. The reported preliminary lag measurements are for intermediate-luminosity quasars at 0.3<~z<0.8, including nine H{beta} lags and six Mg II lags, for the first time extending RM results to this redshift-luminosity regime and providing direct quasar black hole mass estimates over approximately half of cosmic time. The Mg II lags also increase the number of known Mg II lags by several fold and start to explore the utility of Mg II for RM at high redshift. The location of these new lags at higher redshifts on the observed BLR size-luminosity relationship is statistically consistent with previous H{beta} results at z<0.3. However, an independent constraint on the relationship slope at z>0.3 is not yet possible owing to the limitations in our current sample. Our results demonstrate the general feasibility and potential of multi-object RM for z>0.3 quasars.
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1342. LAMOST DR5 catalogs
- ID:
- ivo://CDS.VizieR/V/164
- Title:
- LAMOST DR5 catalogs
- Short Name:
- V/164
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We totally published 9,026,365 targets in this table, including 8,183,160 stars, 152,863 galaxies, 52,453 quasars, and 637,889 unknown objects. In addition, there are 5,808,985 objects with g band S/Ns larger than 10, 7,701,235 objects with i band S/Ns larger than 10, and 5,734,239 objects with g band S/Ns larger than 10 and i band S/Ns larger than 10. On the website http://dr5.lamost.org/catalogue, we provide two format LAMOST general catalogs, which include a FITS table and a CSV table, and the two catalog files have the same contents.
1343. LAMOST DR4 catalogs
- ID:
- ivo://CDS.VizieR/V/153
- Title:
- LAMOST DR4 catalogs
- Short Name:
- V/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a Chinese national scientific research facility operated by the National Astronomical Observatories, Chinese Academy of Sciences. It is a special reflecting Schmidt telescope with 4000 fibers in a field of view of 20 deg22in the sky. Until July 2016, LAMOST has completed its pilot survey which was launched in October 2011 and ended in June 2012, and the first four years of regular survey which was initiated on September 2012. After this five-year-survey, we totally obtain 7,617,035 spectra, which consist of stars, galaxies, quasars and other unknown objects. Now, the fourth data release (DR4) has published online (http://dr4.lamost.org/), and released data products include 1. Spectra. - In general, there are 7,617,035 flux- and wavelength-calibrated, sky-subtracted spectra in DR4, including 6,943,865 stars, 117,254 galaxies, 36,575 quasars, and 519,341 unknown objects, and these spectra cover the wavelength range of 3690-9100 angstrom with a resolution of 1800 at the 5500 angstrom. 2. Spectroscopic Parameters Catalogs. - In this data release, six spectroscopic parameters catalogs are also published, they are the LAMOST general catalog, the A, F, G and K type star catalog, the A type star catalog, the M dwarf catalog, the observed plate information catalog, and the input catalog respectively. For the first four catalogs, they all include 36 columns of basic spectroscopic information, for example, right ascension, declination, signal to noise ratio, magnitude, classification and redshift. Also, the A type star catalog publish line indices of six spectral lines and four balmer line widths at 20% below the local continua, the A, F, G and K type star catalog provides effective temperature, surface gravity, and metallicity, and the M dwarf catalog releases the equivalent width of Halpha line, ten line indices, one metallicity sensitive parameter and a flag that indicates whether or not exist magnetic activity. For the observed plate information catalog, it mainly contains nine basic plate information for all published plates. At last, the input catalog includes 24 basic fields mentioned above, and three new fields which are not included in the above catalogs.
1344. LAMOST DR2 catalogs
- ID:
- ivo://CDS.VizieR/V/149
- Title:
- LAMOST DR2 catalogs
- Short Name:
- V/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs.
1345. LAMOST DR1 catalogs
- ID:
- ivo://CDS.VizieR/V/146
- Title:
- LAMOST DR1 catalogs
- Short Name:
- V/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey is a spectroscopic survey that will eventually cover approximately half of the celestial sphere and collect 10 million spectra of stars, galaxies and QSOs. Objects in both the pilot survey and the first year regular survey are included in the LAMOST DR1. The pilot survey started in October 2011 and ended in June 2012, and the data have been released to the public as the LAMOST Pilot Data Release in August 2012. The regular survey started in September 2012, and completed its first year of operation in June 2013. The LAMOST DR1 includes a total of 1202 plates containing 2955336 spectra, of which 1790879 spectra have observed signal-to-noise ratio (SNR)>=10. All data with SNR>=2 are formally released as LAMOST DR1 under the LAMOST data policy. This data release contains a total of 2204696 spectra, of which 1944329 are stellar spectra, 12082 are galaxy spectra and 5017 are quasars. The DR1 not only includes spectra, but also three stellar catalogs with measured parameters: late A,FGK-type stars with high quality spectra (1061918 entries), A-type stars (100073 entries), and M-type stars (121522 entries). This paper introduces the survey design, the observational and instrumental limitations, data reduction and analysis, and some caveats. A description of the FITS structure of spectral files and parameter catalogs is also provided.
- ID:
- ivo://org.gavo.dc/lamost6/q/svc_lrs
- Title:
- LAMOST DR6 Low Resolution Spectra
- Short Name:
- LM6 LRS SSAP
- Date:
- 27 Dec 2024 08:31:05
- Publisher:
- The GAVO DC team
- Description:
- A machine-readable interface to the LAMOST6 low resolution spectra based on SSAP and datalink.
- ID:
- ivo://org.gavo.dc/lamost6/q/svc_mrs
- Title:
- LAMOST DR6 Medium Resolution Spectra
- Short Name:
- LM6 MRS SSAP
- Date:
- 27 Dec 2024 08:31:05
- Publisher:
- The GAVO DC team
- Description:
- A machine-readable interface to the LAMOST6 medium resolution spectra based on SSAP and datalink.
- ID:
- ivo://org.gavo.dc/lamost5/q/ssa
- Title:
- LAMOST DR5 survey spectra
- Short Name:
- LAMOST DR5 SSAP
- Date:
- 27 Dec 2024 08:31:13
- Publisher:
- The GAVO DC team
- Description:
- This services provides 1D spectra from DR5 of LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) through SSAP; data is served both in VO-standard SDM and, via datalink, the original SDSS-inspired FITS described in http://dr5.lamost.org/doc/data-production-description .
- ID:
- ivo://CDS.VizieR/J/ApJS/251/15
- Title:
- LAMOST-Kepler/K2 survey (LK-MRS) first year obs.
- Short Name:
- J/ApJS/251/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Phase II of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST)-Kepler/K2 survey (LK-MRS), initiated in 2018, aims at collecting medium-resolution spectra (R~7500; hereafter MRS) for more than 50000 stars with multiple visits (~60 epochs) over a period of 5yr (2018 September to 2023 June). We selected 20 footprints distributed across the Kepler field and six K2 campaigns, with each plate containing a number of stars ranging from ~2000 to ~3000. During the first year of observations, the LK-MRS has already visited 13 plates 223 times over 40 individual nights, and collected ~280000 and ~369000 high-quality spectra in the blue and red wavelength ranges, respectively. The atmospheric parameters and radial velocities for ~259000 spectra of 21053 targets were successfully calculated by the LAMOST stellar parameter pipeline. The internal uncertainties for the effective temperature, surface gravity, metallicity, and radial velocity are found to be 100K, 0.15dex, 0.09dex, and 1.00km/s, respectively, when derived from a medium-resolution LAMOST spectrum with a signal-to-noise ratio (S/N) in the g band of 10. All of the uncertainties decrease as S/N increases, but they stabilize for S/N>100. We found 14997, 20091, and 1514 stars in common with the targets from the LAMOST low-resolution survey (LRS), Gaia, and the Apache Point Observatory Galactic Evolution Experiment (APOGEE), respectively, corresponding to fractions of ~70%, ~95%, and ~7.2%. In general, the parameters derived from LK-MRS spectra are consistent with those obtained from the LRS and APOGEE spectra, but the scatter increases as the surface gravity decreases when comparing with the measurements from APOGEE. A large discrepancy is found with the Gaia values of the effective temperature. Comparisons of the radial velocities of LK-MRS to Gaia and LK-MRS to APOGEE nearly follow a Gaussian distribution with means of {mu}~1.10 and 0.73km/s, respectively. We expect that the results from the LK-MRS spectra will shed new light on binary stars, asteroseismology, stellar activity, and other research fields.
- ID:
- ivo://CDS.VizieR/J/other/RAA/17.41
- Title:
- LAMOST metal-poor galaxies sample
- Short Name:
- J/other/RAA/17.4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 48 metal-poor galaxies at z<0.14 selected from 92 510 galaxies in the LAMOST survey. These galaxies are identified by their detection of the auroral emission line [OIII]{lambda}4363 above the 3{sigma} level, which allows a direct measurement of electron temperature and oxygen abundance. The emission line fluxes are corrected for internal dust extinction using the Balmer decrement method. With electron temperature derived from [OIII]{lambda}{lambda}4959,5007/[OIII]{lambda}4363 and electron density from [SII]{lambda}6731/[SII]{lambda}6717, we obtain the oxygen abundances in our sample which range from 12+log(O/H)=7.63(0.09Z_{sun}_) to 8.46 (0.6Z_{sun}_). We find an extremely metal-poor galaxy with 12+log(O/H)=7.63+/-0.01. With multiband photometric data from FUV to NIR and H{alpha} measurements, we also determine the stellar masses and star formation rates, based on the spectral energy distribution fitting and H{alpha} luminosity, respectively. We find that our galaxies have low and intermediate stellar masses with 6.39<=log(M/M_{sun}_)<=9.27, and high star formation rates (SFRs) with -2.18<=log(SFR/M_{sun}_yr^-1^)<=1.95. We also find that the metallicities of our galaxies are consistent with the local T_e_-based mass-metallicity relation, while the scatter is about 0.28dex. Additionally, assuming the coefficient of {alpha}=0.66, we find most of our galaxies follow the local mass-metallicity-SFR relation, but a scatter of about 0.24dex exists, suggesting the mass-metallicity relation is weakly dependent on SFR for those metal-poor galaxies.
