- ID:
- ivo://CDS.VizieR/J/MNRAS/501/2848
- Title:
- Spectrophotometric standard cand. photometry
- Short Name:
- J/MNRAS/501/2848
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Johnson-Kron-Cousins BVRI photometry of 228 candidate spectrophotometric standard stars for the external (absolute) flux calibration of Gaia data. The data were gathered as part of a 10-yr observing campaign with the goal of building the external grid of flux standards for Gaia and we obtained absolute photometry, relative photometry for constancy monitoring, and spectrophotometry. Preliminary releases of the flux tables were used to calibrate the first two Gaia releases. This paper focuses on the imaging frames observed in good sky conditions (about 9100). The photometry will be used to validate the ground-based flux tables of the Gaia spectrophotometric standard stars and to correct the spectra obtained in non-perfectly photometric observing conditions for small zero-point variations. The absolute photometry presented here is tied to the Landolt standard stars system to ~1 per cent or better, depending on the photometric band. Extensive comparisons with various literature sources show an overall ~1 per cent agreement, which appears to be the current limit in the accuracy of flux calibrations across various samples and techniques in the literature. The Gaia photometric precision is presently of the order of 0.1 per cent or better, thus various ideas for the improvement of photometric calibration accuracy are discussed.
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- ID:
- ivo://CDS.VizieR/J/AZh/78/1135
- Title:
- Spectrophotometric standards near DE=+40{deg}
- Short Name:
- J/AZh/78/1135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The second stage to compile a list of regional intermediate-brightness spectrophotometric standards has been completed. It includes the spectral energy distribution for 24 stars with magnitudes 7.0-8.5 near +40{deg} declination. The range 3100-7600{AA} was studied with a spectral resolution of 50{AA}. All the stars are referenced to a single standard the circumpolar star HD 221525. The energy distributions were used to compute color indices in the UBV, WBVR, and UPXYZVS systems,as well as in the system (BT,VT) of the TYCHO catalog.
- ID:
- ivo://CDS.VizieR/J/AJ/114/699
- Title:
- Spectrophotometry in open clusters
- Short Name:
- J/AJ/114/699
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectrophotometry is presented for 237 stars in 7 nearby open clusters: Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, and M39. The observations were taken by Lee McDonald and David Burstein using the Wampler single-channel scanner on the Crossley 0.9m telescope at Lick Observatory from 1973 July through 1974 December. Sixteen bandpasses spanning the spectral range 3500-7780{AA} were observed for each star, with bandwidths 32, 48, or 64{AA}. Data are standardized to the Hayes-Latham system to mutual accuracy of 0.016mag per passband. The accuracy of the spectrophotometry is assessed in three ways on a star-by-star basis. First, comparisons are made with previously published spectrophotometry for 19 stars observed in common. Second, (B-V) colors and uvby colors are compared for 236 stars and 221 stars, respectively. Finally, comparisons are made for 200 main sequence stars to the spectral synthesis models of Kurucz, fixing logg=4.0 and [Fe/H]=0.0, and only varying effective temperature. The accuracy of tests using uvby colors and the Kurucz models are shown to track each other closely, yielding an accuracy estimate (1{sigma}) of 0.01mag for the 13 colors formed from bandpasses longward of the Balmer jump, and 0.02mag for the 3 colors formed from the three bandpasses below the Balmer jump. In contrast, larger scatter is found relative to the previously published spectrophotometry of Bohm-Vitense & Johnson (1977ApJS...35..461B) (16 stars in common) and Gunn & Stryker (1983, Cat. <III/88>) (3 stars). We also show that the scatter in the fits of the spectrophotometric colors and the uvby filter colors is a reasonable way to identify the observations of which specific stars are accurate to 1{sigma}, 2{sigma}, .... As such, the residuals from both the filter color fits and the Kurucz model fits are tabulated for each star where it was possible to make a comparison, so users of these data can choose stars according to the accuracy of the data that is appropriate to their needs. The very good agreement between the models and these data verifies the accuracy of these data, and also verifies the usefulness of the Kurucz models to define spectrophotometry for stars in this temperature range (>5000K). These data define accurate spectrophotometry of bright, open cluster stars that can be used as a secondary flux calibration for CCD-based spectrophotometric surveys. (c) 1997 American Astronomical Society.
- ID:
- ivo://CDS.VizieR/J/ApJ/695/1591
- Title:
- Spectrophotometry in PEARS fields
- Short Name:
- J/ApJ/695/1591
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep ACS slitless grism observations and identification of stellar sources are presented within the Great Observatories Origins Deep Survey North and South fields which were obtained in the Probing Evolution And Reionization Spectroscopically (PEARS) program. It is demonstrated that even low-resolution spectra can be a very powerful means of identifying stars in the field, especially low-mass stars with stellar types M0 and later. The PEARS fields lay within the larger GOODS fields, and we used new, deeper images to further refine the selection of stars in the PEARS field, down to a magnitude of z_850_=25 using a newly developed stellarity parameter. The total number of stars with reliable spectroscopic and morphological identification was 95 and 108 in the north and south fields, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJS/126/331
- Title:
- Spectrophotometry of nearby field galaxies
- Short Name:
- J/ApJS/126/331
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained integrated and nuclear spectra as well as U, B, R surface photometry for a representative sample of 196 nearby galaxies. These galaxies span the entire Hubble sequence in morphological type, as well as a wide range of luminosities (M_B_=-14 to -22). Here we present the spectrophotometry for these galaxies. The selection of the sample and the U, B, R surface photometry is described in a companion paper (J/ApJS/126/271).
- ID:
- ivo://CDS.VizieR/J/ApJS/164/81
- Title:
- Spectrophotometry of nearby galaxies
- Short Name:
- J/ApJS/164/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present integrated optical spectrophotometry for a sample of 417 nearby galaxies. Our observations consist of spatially integrated, S/N=10-100 spectroscopy between 3600 and 6900{AA} at ~8{AA} FWHM resolution. In addition, we present nuclear (2.5"x2.5") spectroscopy for 153 of these objects. Our sample targets a diverse range of galaxy types, including starbursts, peculiar galaxies, interacting/merging systems, dusty, infrared-luminous galaxies, and a significant number of normal galaxies. We use population synthesis to model and subtract the stellar continuum underlying the nebular emission lines. This technique results in emission-line measurements reliably corrected for stellar absorption. Here we present the integrated and nuclear spectra, the nebular emission-line fluxes and equivalent widths, and a comprehensive compilation of ancillary data available in the literature for our sample.
- ID:
- ivo://CDS.VizieR/J/A+A/417/499
- Title:
- Spectrophotometry of Virgo cluster galaxies
- Short Name:
- J/A+A/417/499
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Drift-scan mode (3600-6800{AA}) spectra with 500<R<1000 resolution are presented for 333 galaxies members to nearby clusters, covering the whole Hubble sequence. The majority (225) were obtained for galaxies in the Virgo cluster where a completeness of 36%, if all Hubble types are considered, and of 5 %, restricting to late-types, was reached at mp<=16. Our data can be therefore considered representative of the integrated spectral properties of giant and dwarf galaxies in this cluster. Intensities and equivalent widths (EWs) are derived for the principal lines, both in emission and in absorption. Deblending of the underlying absorption from emission was achieved in most cases.
- ID:
- ivo://CDS.VizieR/J/AJ/147/16
- Title:
- Spectroscocpy of planetary nebulae in M31
- Short Name:
- J/AJ/147/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed a method to identify planetary nebula (PN) candidates in imaging data of the Sloan Digital Sky Survey (SDSS). This method exploits the SDSS's five-band sampling of emission lines in PN spectra, which results in a color signature distinct from that of other sources. Selection criteria based on this signature can be applied to nearby galaxies in which PNe appear as point sources. We applied these criteria to the whole area of M31 as scanned by the SDSS, selecting 167 PN candidates that are located in the outer regions of M31. The spectra of 80 selected candidates were then observed with the 2.2m telescope at Calar Alto Observatory. These observations and cross-checks with literature data show that our method has a selection rate efficiency of about 90%, but the efficiency is different for the different groups of PN candidates. In the outer regions of M31, PNe trace different well-known morphological features like the Northern Spur, the NGC 205 Loop, the G1 Clump, etc. In general, the distribution of PNe in the outer region 8<R<20kpc along the minor axis shows the "extended disk"-a rotationally supported low surface brightness structure with an exponential scale length of 3.21+/-0.14kpc and a total mass of ~10^10^M_{sun}_, which is equivalent to the mass of M33. We report the discovery of three PN candidates with projected locations in the center of Andromeda NE, a very low surface brightness giant stellar structure in the outer halo of M31. Two of the PNe were spectroscopically confirmed as genuine PNe. These two PNe are located at projected distances along the major axis of ~48Kpc and ~41Kpc from the center of M31 and are the most distant PNe in M31 found up to now. With the new PN data at hand we see the obvious kinematic connection between the continuation of the Giant Stream and the Northern Spur. We suggest that 20%-30% of the stars in the Northern Spur area may belong to the Giant Stream. In our data we also see a possible kinematic connection between the Giant Stream and PNe in Andromeda NE, suggesting that Andromeda NE could be the core or remnant of the Giant Stream. Using PN data we estimate the total mass of the Giant Stream progenitor to be {approx}10^9^M_{sun}_. About 90% of its stars appear to have been lost during the interaction with M31.
- ID:
- ivo://CDS.VizieR/J/ApJ/866/22
- Title:
- Spectroscopic analysis of Tuc III stream
- Short Name:
- J/ApJ/866/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic study of the tidal tails and core of the Milky Way satellite Tucana III, collectively referred to as the Tucana III stream, using the 2dF+AAOmega spectrograph on the Anglo-Australian Telescope and the IMACS spectrograph on the Magellan Baade Telescope. In addition to recovering the brightest nine previously known member stars in the Tucana III core, we identify 22 members in the tidal tails. We observe strong evidence for a velocity gradient of 8.0+/-0.4km/s/deg over at least 3{deg} on the sky. Based on the continuity in velocity, we confirm that the Tucana III tails are real tidal extensions of Tucana III. The large velocity gradient of the stream implies that Tucana III is likely on a radial orbit. We successfully obtain metallicities for four members in the core and 12 members in the tails. We find that members close to the ends of the stream tend to be more metal-poor than members in the core, indicating a possible metallicity gradient between the center of the progenitor halo and its edge. The spread in metallicity suggests that the progenitor of the Tucana III stream is likely a dwarf galaxy rather than a star cluster. Furthermore, we find that with the precise photometry of the Dark Energy Survey data, there is a discernible color offset between metal-rich disk stars and metal-poor stream members. This metallicity-dependent color offers a more efficient method to recognize metal-poor targets and will increase the selection efficiency of stream members for future spectroscopic follow-up programs on stellar streams.
- ID:
- ivo://CDS.VizieR/J/AJ/151/6
- Title:
- Spectroscopic and photometric properties of Tombaugh 1
- Short Name:
- J/AJ/151/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Open clusters can be the key to deepening our knowledge on various issues involving the structure and evolution of the Galactic disk and details of stellar evolution because a cluster's properties are applicable to all its members. However, the number of open clusters with detailed analysis from high-resolution spectroscopy or precision photometry imposes severe limitations on studies of these objects. To expand the number of open clusters with well-defined chemical abundances and fundamental parameters, we investigate the poorly studied, anticenter open cluster Tombaugh 1. Using precision uvbyCaH{beta} photometry and high-resolution spectroscopy, we derive the cluster's reddening, obtain photometric metallicity estimates, and, for the first time, present a detailed abundance analysis of 10 potential cluster stars (nine clump stars and one Cepheid). Using the radial position from the cluster center and multiple color indices, we have isolated a sample of unevolved, probable single-star members of Tombaugh 1. From 51 stars, the cluster reddening is found to be E(b-y)=0.221+/-0.006 or E(B-V)=0.303+/-0.008, where the errors refer to the internal standard errors of the mean. The weighted photometric metallicity from m_1_ and hk is [Fe/H]=-0.10+/-0.02, while a match to the Victoria-Regina Stromgren isochrones leads to an age of 0.95+/-0.10 Gyr and an apparent modulus of (m-M)=13.10+/-0.10. Radial velocities identify six giants as probable cluster members, and the elemental abundances of Fe, Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Y, Ba, Ce, and Nd have been derived for both the cluster and the field stars. Tombaugh 1 appears to be a typical inner thin disk, intermediate-age open cluster of slightly subsolar metallicity, located just beyond the solar circle, with solar elemental abundance ratios except for the heavy s-process elements, which are a factor of two above solar. Its metallicity is consistent with a steep metallicity gradient in the galactocentric region between 9.5 and 12 kpc. Our study also shows that Cepheid XZ CMa is not a member of Tombaugh 1 and reveals that this Cepheid presents signs of barium enrichment, making it a probable binary star.
