- ID:
- ivo://CDS.VizieR/J/ApJ/855/134
- Title:
- UV spectrum of molecular hydrogen in the Sun
- Short Name:
- J/ApJ/855/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650km in standard one-dimensional (1D) models of the quiet Sun, near the {tau}=1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550{AA} is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.
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- ID:
- ivo://CDS.VizieR/J/ApJS/213/11
- Title:
- UV spectrum of the quiet Sun above the limb
- Short Name:
- J/ApJS/213/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the absolute calibration of the EUV Imaging Spectrometer (EIS) on Hinode by comparing EIS full-disk mosaics with irradiance observations from the EUV Variability Experiment on the Solar Dynamics Observatory. We also use extended observations of the quiet corona above the limb combined with a simple differential emission measure model to establish new effective area curves that incorporate information from the most recent atomic physics calculations. We find that changes to the EIS instrument sensitivity are a complex function of both time and wavelength. We find that the sensitivity is decaying exponentially with time and that the decay constants vary with wavelength. The EIS short wavelength channel shows significantly longer decay times than the long wavelength channel.
- ID:
- ivo://CDS.VizieR/J/ApJS/143/377
- Title:
- UV-to-FIR magnitudes for 83 starburst galaxies
- Short Name:
- J/ApJS/143/377
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a database of UV-to-FIR data of 83 nearby starburst galaxies. The galaxies are selected based upon the availability of IUE data. We have recalibrated the IUE UV spectra for these galaxies by incorporating the most recent improvements. For 45 of these galaxies we use observations by Storchi-Bergmann et al. (1995ApJS...98..103S) and McQuade et al. (1995ApJS...97..331M) for the spectra in the optical range. The NIR data are from new observations obtained at the NASA/IRTF and the Mount Laguna Observatory, combined with the published results from observations at the Kitt Peak National Observatory. In addition, published calibrated ISO data are included to provide mid-IR flux densities for some of the galaxies. The optical-to-IR data are matched as closely as possible to the IUE large aperture. In conjunction with IRAS and ISO FIR flux densities, all these data form a set of observed spectral energy distributions (SEDs) of the nuclear regions of nearby starburst galaxies. The SEDs should be useful in studying star formation and dust/gas attenuation in galaxies. We also present the magnitudes in the standard BVRI and various HST/WFPC2 bandpasses synthesized from the UV and optical wavelength ranges of these SEDs. For some of the galaxies, the HST/WFPC2 magnitudes synthesized from the SEDs are checked with those directly measured from WFPC2 images to test the photometric errors of the optical data and their effective matching of apertures with the UV data. The implications of the new SEDs on the star formation rates and dust/gas attenuation are briefly discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/898/166
- Title:
- UV to NIR obs. of SN 2019ehk
- Short Name:
- J/ApJ/898/166
- Date:
- 21 Mar 2022 09:18:33
- Publisher:
- CDS
- Description:
- We present panchromatic observations and modeling of the Calcium-rich supernova (SN) 2019ehk in the star-forming galaxy M100 (d~16.2Mpc) starting 10hr after explosion and continuing for ~300days. SN 2019ehk shows a double-peaked optical light curve peaking at t=3 and 15days. The first peak is coincident with luminous, rapidly decaying Swift-XRT-discovered X-ray emission (L_x_~10^41^erg/s at 3days; Lx{propto}t^-3^), and a Shane/Kast spectral detection of narrow H{alpha} and HeII emission lines (v~500km/s) originating from pre-existent circumstellar material (CSM). We attribute this phenomenology to radiation from shock interaction with extended, dense material surrounding the progenitor star at r<10^15^cm and the resulting cooling emission. We calculate a total CSM mass of ~7x10^-3^M_{sun}_ (M_He_/M_H_~6) with particle density n~10^9^cm^-3^. Radio observations indicate a significantly lower density n<10^4^cm^-3^ at larger radii r>(0.1-1)x10^17^cm. The photometric and spectroscopic properties during the second light-curve peak are consistent with those of Ca-rich transients (rise-time of t_r_=13.4!+/-0.210days and a peak B-band magnitude of M_B_=-15.1+/-0.200mag). We find that SN 2019ehk synthesized (3.1+/-0.11)x10^-2^M_{sun}_ of ^56^Ni and ejected M_ej_=(0.72+/-0.040)M_{sun}_ total with a kinetic energy E_k_=(1.8+/-0.10)x10^50^erg. Finally, deep HST pre-explosion imaging at the SN site constrains the parameter space of viable stellar progenitors to massive stars in the lowest mass bin (~10M_{sun}_) in binaries that lost most of their He envelope or white dwarfs (WDs). The explosion and environment properties of SN 2019ehk further restrict the potential WD progenitor systems to low-mass hybrid HeCO WD+CO WD binaries.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/47
- Title:
- UV to NIR spectra of the QSO 2MASS J15165323+1900482
- Short Name:
- J/ApJ/900/47
- Date:
- 21 Mar 2022 09:27:00
- Publisher:
- CDS
- Description:
- We present detailed studies of the partially obscured quasar 2MASSJ151653.23+190048.2 with continuous broadband spectrophotometry from near-infrared (NIR) through optical to ultraviolet (UV). The NIR and optical spectra show strong broad emission lines, while the UV spectrum is dominated by a set of rich intermediate-width emission lines (IELs). These IELs, unshifted with respect to the quasar systemic velocity measured by narrow emission lines, share a common profile of about 1900km/s in FWHM, in contrast to the Balmer and Paschen broad emission lines of FWHM ~6300km/s observed in the optical and NIR. The intermediate width of these lines indicates that the emitting gas may come from the dusty torus region. However, the observed peculiar IEL intensity ratios, such as NV{lambda}1240/Ly{alpha}, indicate that the emitting gas has a very high density, up to ~10^13^cm^-3^. Such a high density is unusual for gas around the dusty torus region, except that we consider mechanisms such as shocks that can produce local ultradense gas. We speculate that these emission lines could originate from the shock region, possibly induced by the quasar outflow colliding with the inner wall of the dusty torus. If true, this may give us an opportunity to peep at the quasar outflows at the scale of the dusty torus that have so far been elusive due to the limited resolving powers of existing facilities.
- ID:
- ivo://CDS.VizieR/J/A+A/402/37
- Title:
- UV to radio SED of galaxies in Virgo cluster
- Short Name:
- J/A+A/402/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multifrequency dataset for an optically-selected, volume-limited, complete sample of 118 late-type galaxies (>=S0a) in the Virgo cluster. The database includes UV, visible, near-IR, mid-IR, far-IR, radio continuum photometric data as well as spectroscopic data of H{alpha}, CO and HI lines, homogeneously reduced, obtained from our own observations or compiled from the literature. Assuming the energy balance between the absorbed stellar light and that radiated in the IR by dust, we calibrate an empirical attenuation law suitable for correcting photometric and spectroscopic data of normal galaxies. The data, corrected for internal extinction, are used to construct the spectral energy distribution (SED) of each individual galaxy, and combined to trace the median SED of galaxies in various classes of morphological type and luminosity.
- ID:
- ivo://CDS.VizieR/J/A+AS/121/461
- Title:
- UV variability of Fairall-9
- Short Name:
- J/A+AS/121/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is a study of the UV variability of the galaxy Fairall-9 between 1978 and 1991. Table 1 shows the UV continuum fluxes measured in three "line-free" windows centered at 1171, 1400 and 1910 A (observed wavelengths), and corrected for E(B-V)=0.035 extinction. The IUE Fine Error Sensor (FES) counts (optical photometry) are also given in this table, corrected for the same extinction. Tables 10, 11, 12 and 13 show the variability of the components for the main UV lines (Ly{alpha}+NV, SiIV, CIV and MgII). Line profile variability has been used to isolate four gaussian line components, which are sufficient to describe all lines at all levels of brightness in a consistent way: one narrow (i.e. unresolved at the IUE resolution) and three broad components: a central (velocity same as the narrow line), a redshifted (v=3300 km/s) and a blue shifted one (v=-3600 km/s). The Ly{alpha}-NV blend is fitted together in the Ly{alpha} region (Table 10), to account the NV presence (one narrow and one red component). The results for SiIV are shown in Table 11. In CIV (Table 12) have been included a very weak component bluer than the blue component, most likely associated with NIV] 1486. Table 13 shows MgII results.
- ID:
- ivo://CDS.VizieR/J/A+AS/128/361
- Title:
- Vacuum ultraviolet emission band systems of N2
- Short Name:
- J/A+AS/128/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observed wavenumbers of the emission lines belonging to 10 vacuum ultraviolet band systems of molecular nitrogen are classified into 283 bands, 220 of them reported for the first time
- ID:
- ivo://CDS.VizieR/J/AJ/156/78
- Title:
- 44 validated planets from K2 Campaign 10
- Short Name:
- J/AJ/156/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 44 validated planets from the 10th observing campaign of the NASA K2 mission, as well as high-resolution spectroscopy and speckle imaging follow-up observations. These 44 planets come from an initial set of 72 vetted candidates, which we subjected to a validation process incorporating pixel-level analyses, light curve analyses, observational constraints, and statistical false positive probabilities. Our validated planet sample has median values of R_p_=2.2 R_{Earth}_, P_orb_=6.9 days, T_eq_=890 K, and J=11.2 mag. Of particular interest are four ultra-short period planets (P_orb_~<1 day), 16 planets smaller than 2 R_{Earth}_, and two planets with large predicted amplitude atmospheric transmission features orbiting infrared-bright stars. We also present 27 planet candidates, most of which are likely to be real and worthy of further observations. Our validated planet sample includes 24 new discoveries and has enhanced the number of currently known super-Earths (R_p_~1-2 R_{Earth}_), sub-Neptunes (R_p_~2-4 R_{Earth}_), and sub-Saturns (R_p_~4-8 R_{Earth}_) orbiting bright stars (J=8-10 mag) by ~4%, ~17%, and ~11%, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJS/215/20
- Title:
- Vanadium log(gf) and transition probabilities
- Short Name:
- J/ApJS/215/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New emission branching fraction measurements for 836 lines of the first spectrum of vanadium (VI) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1m Fourier transform spectrometer (FTS) and a high-resolution echelle spectrometer. The branching fractions are combined with recently published radiative lifetimes from laser-induced fluorescence measurements to determine accurate absolute atomic transition probabilities for the 836 lines. The FTS data are also used to extract new hyperfine structure A coefficients for 26 levels of neutral vanadium. These new laboratory data are applied to determine the V abundance in the Sun and metal-poor star HD 84937, yielding log{epsilon}(V)=3.956+/-0.004 ({sigma}=0.037) based on 93 VI lines and log{epsilon}(V)=1.89+/-0.03 ({sigma}=0.07) based on nine VI lines, respectively, using the Holweger-Muller 1D model. These new VI abundance values for the Sun and HD 84937 agree well with our earlier determinations based upon VII.
