- ID:
- ivo://CDS.VizieR/J/AJ/158/129
- Title:
- Near-infrared hydrogen & helium QSO emission lines
- Short Name:
- J/AJ/158/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 14 near-infrared (NIR) quasar spectra observed with the Flamingos-2 NIR spectrometer instrument at the Gemini South Observatory. The targets were selected with redshifts of (0.58~<z~<0.63) to ensure the spectral wavelength range included specifically identified hydrogen and helium broad emission lines. We present measurements of their FWHM, equivalent widths, and flux ratios relative to H{alpha}. The quasars are all within the Sloan Digital Sky Survey (SDSS) Stripe 82 region which, then also provides multi-epoch rest-frame UV and optical spectroscopic observations of our targets. In future work, these data and those from Galaxy Evolution Explorer and NUV spectra will be utilized to constrain photoionization models to determine physical conditions within the broad emission line regions, such as the incident ionizing photon flux and gas density.
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- ID:
- ivo://CDS.VizieR/J/A+A/642/L15
- Title:
- Near-infrared spectra for TW Hya
- Short Name:
- J/A+A/642/L15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Volatile molecules are critical to terrestrial planetary habitability, yet they are difficult to observe directly where planets form at the midplanes of protoplanetary disks. It is unclear whether the inner ~1AU of disks are volatile-poor or if this region is resupplied with ice-rich dust from colder disk regions. Dust traps at radial pressure maxima bounding disk gaps can cut off the inner disk from these types of volatile reservoirs. However, the trap retention efficiency and atomic composition of trapped dust have not been measured. We present a new technique to measure the absolute atomic abundances in the gas accreting onto T Tauri stars and infer the bulk atomic composition and distribution of midplane solids that have been retained in the disk around the young star TW Hya. We identify near-infrared atomic line emission from gas-phase material inside the dust sublimation rim of TW Hya. Gaussian decomposition of the strongest H Paschen lines isolates the inner disk hydrogen emission. We measure several key elemental abundances, relative to hydrogen, using a chemical photoionization model and infer dust retention in the disk. With a 1D transport model, we determine approximate radial locations and retention efficiencies of dust traps for different elements. Volatile and refractory elements are depleted from TW Hya's hot gas by factors of ~10^2^ and up to 10^5^, respectively. The abundances of the trapped solids are consistent with a combination of primitive Solar System bodies. Dust traps beyond the CO and N_2_ snow line cumulatively sequester 96% of the total dust flux, while the trap at 2AU, near the H_2_O snow line, retains 3%. The high depletions of Si, Mg, and Ca are explained by a third trap at 0.3AU with >95% dust retention. TW Hya sports a significant volatile reservoir rich in C- and N-ices in its outer submillimeter ring structure. However, unless the inner disk was enhanced in C by earlier radial transport, typical C destruction mechanisms and the lack of a C resupply should leave the terrestrial planet-forming region of TW Hya "dry" and carbon-poor. Any planets that form within the silicate dust trap at 0.3 AU could resemble Earth in terms of the degree of their volatile depletion.
- ID:
- ivo://CDS.VizieR/J/AJ/121/362
- Title:
- Near-Infrared Spectra of IC5117
- Short Name:
- J/AJ/121/362
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared spectroscopy from 0.8 to 2.5{mu}m is presented for the planetary nebula IC5117. The emission lines of IC5117 span a wide range of ionization that includes He II, [S III], [S II], [N I], and H2. The reddening measured from the hydrogen lines is E(B-V)=0.79, most of which is probably interstellar in origin. The He/H abundance ratio is 0.113+/-0.015, with approximately 10% of the helium being doubly ionized. Using our measurements of [S II] and [S III] lines and published observations of [S IV], we find a sulfur abundance, relative to hydrogen, of N(S)/N(H)=7.8 x 10^-6^, or approximately half the solar value. Fluxes and flux limits for several lines of molecular hydrogen are presented. Measurements of 1-0 transitions, together with the limits on 2-1 transitions, indicate Tvib~Trot=1900K, suggesting a purely collisional excitation mechanism. The ortho-to-para ratio is ~3, a value that is also indicative of collisional excitation. The presence of [C I] {lambda}9850 is consistent with previous studies of IC 5117 that indicated carbon is more abundant than oxygen. IC5117 follows the trend of planetary nebulae that display bipolar outflows and H2 emission to be carbon-rich. We confirm the results of Zhang & Kwok, who reported infrared continuum emission substantially in excess of that produced by the ionized gas. This emission is most likely due to hot dust (T~1300K) and accounts for roughly half of the continuum between 1.5 and 2{mu}m.
- ID:
- ivo://CDS.VizieR/III/181
- Title:
- Near Infrared Spectra of Normal Stars
- Short Name:
- III/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The authors present digital spectra of O to M stars, luminosity classes V, III, and Ib in the wavelength range 5750-8950{AA}, at 15.5{AA} resolution. The stars follow well defined morphological sequences in both temperature and luminosity. This wavelength region and resolution, combined with the high sensitivity of silicon-based detectors, are very useful for spectral classification. Details of the observations, identifications of the main spectral features, and spectral lines most sensitive to temperature and luminosity are given in the paper.
- ID:
- ivo://CDS.VizieR/J/ApJ/640/579
- Title:
- Near-infrared spectra of 27 SDSS quasars
- Short Name:
- J/ApJ/640/579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a near-infrared quasar composite spectrum spanning the wavelength range 0.58-3.5um. The spectrum has been constructed from observations of 27 quasars obtained at the NASA IRTF telescope and satisfying the criteria Ks<14.5 and M_i_<-23; the redshift range is 0.118<z<0.418. The signal-to-noise ratio is moderate, reaching a maximum of 150 between 1.6 and 1.9um. While a power-law fit to the continuum of the composite spectrum requires two breaks, a single power-law slope of alpha=-0.92 plus a 1260K blackbody provides an excellent description of the spectrum from H{alpha} to 3.5um, strongly suggesting the presence of significant quantities of hot dust in this blue-selected quasar sample. We measure intensities and line widths for 10 lines, finding that the Paschen line ratios rule out case B recombination. We compute K-corrections for the J, H, K, and Spitzer 3.6um bands, which will be useful in analyzing observations of quasars up to z=10.
- ID:
- ivo://CDS.VizieR/J/A+A/488/987
- Title:
- Near-infrared survey of R CrA cloud
- Short Name:
- J/A+A/488/987
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To understand low- to intermediate-mass star-formation in the nearby R CrA molecular cloud, we try to identify the stellar content that is accessible with near-infrared observations. We obtained a JHKs band mosaic of ~10'x60' covering the entire R CrA molecular cloud with unprecedented sensitivity. We present a catalogue of about 3500 near-infrared sources fainter than the saturation limit Ks~10mag, reaching Ks~18mag. We analysed the extended sources by inspecting their morphology and point sources by means of colour-colour and colour-magnitude diagrams. Additionally, we compared the extinction inferred from the NIR data with the line-of-sight dust emission at 1.2mm. Sources towards high dust emission but relatively low H-Ks show a projected mm-excess; these sources are either immediately surrounded by cold circumstellar material or, if too red to be a true foreground object, they are embedded in the front layer of the 1.2mm emitting dust cloud. In both cases they are most likely associated with the cloud.
- ID:
- ivo://CDS.VizieR/J/A+A/437/1135
- Title:
- Near-IR astrometry of Southern ICRF quasars
- Short Name:
- J/A+A/437/1135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high quality astrometry, along with J, H, and Ks photometry, for 30 southern International Celestial Reference Frame (ICRF) quasars observed with the ESO NTT/SOFI at La Silla. Our main purpose is to document the optical counterpart of ICRF quasars, by reporting their position in a stellar reference frame and their near-infrared photometry. Our investigation lies within the scope of extending the (radio) extragalactic reference frame into the optical range. An internal precision generally better than 10mas was obtained in positioning the near-infrared counterpart of these quasars within their stellar surroundings. The actual astrometric accuracy is estimated from the departure between the observed and the radio (VLBI) positions of quasars, and is about 35mas, mainly due to the statistical uncertainties of the stellar reference catalogue (UCAC2, Cat. <I/289>). The positional accuracy was improved to 25mas for a subset of 14 quasars observed with extended fields of view, as obtained from mosaics of overlapping images. The 3-band photometry was achieved with a precision most often better than 0.04mag, based on calibration with the 2MASS magnitudes.
- ID:
- ivo://CDS.VizieR/J/A+A/579/A130
- Title:
- Near-IR BN/KL outflow images
- Short Name:
- J/A+A/579/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Adaptive optics images are used to test the hypothesis that the explosive BN/KL outflow from the Orion OMC1 cloud core was powered by the dynamical decay of a non-hierarchical system of massive stars. Narrow-band H_2_, [FeII], and broad-band Ks obtained with the Gemini South multi-conjugate adaptive optics (AO) system GeMS and near-infrared imager GSAOI are presented. The images reach resolutions of 0.08 to 0.10" to the 0.07" diffraction limit of the 8-meter telescope at 2.12um. Comparison with previous AO-assisted observations of sub-fields and other ground-based observations enable measurements of proper motions and the investigation of morphological changes in H_2_ and [FeII] features with unprecedented precision. The images are compared with numerical simulations of compact, high-density clumps moving ~10^3^ times their own diameter through a lower density medium at Mach 10^3^.
- ID:
- ivo://CDS.VizieR/J/A+A/481/123
- Title:
- Near-IR IFU spectroscopy of HH99B
- Short Name:
- J/A+A/481/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim at characterising the morphology and the physical parameters governing the shock physics of the Herbig-Haro object HH99B. We obtained SINFONI-SPIFFI IFU spectroscopy (R~2000-4000) between 1.10 and 2.45{mu}m detecting more than 170 emission lines, that, to a large extent, have never observed before in a Herbig-Haro object. Most of them come from ro-vibrational transitions of molecular hydrogen (v_up_<=7, E_up_~<38000K) and [FeII] (E_up_~<30000K). In addition, we observed several hydrogen and helium recombination lines, along with fine-structure lines of ionic species. All the brightest lines appear resolved in velocity. Intensity ratios of ionic lines were compared with predictions of NLTE models to derive bi-dimensional maps of extinction and electron density, along with estimates of temperature, fractional ionisation, and atomic hydrogen post-shock density. The H2 line intensities were interpreted in the framework of Boltzmann diagrams, from which we have derived extinction and temperature maps of the molecular gas. From the intensity maps of bright lines (i.e. H2 2.122{mu}m and [FeII]1.644{mu}m), the kinematical properties of the shock(s) at work in the region were delineated. Finally, from selected [FeII] lines, constraints on the spontaneous emission coefficients of the 1.257, 1.321, and 1.644{mu}m lines are provided.
- ID:
- ivo://CDS.VizieR/J/A+A/562/A127
- Title:
- Near-IR integral field spectra of 15 M-L dwarfs
- Short Name:
- J/A+A/562/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- At young ages, low surface gravity affects the atmospheric properties of ultracool dwarfs. The impact on medium-resolution near-infrared (NIR) spectra has only been slightly investigated at the M-L transition sofar. We present a library of near-infrared (1.1-2.45um) medium-resolution (R~1500-2000) integral field spectra of 15 young M6-L0 dwarfs. We aim at deriving updated NIR spectral type, luminosity and physical parameters (Teff, logg, M, L/L_{sun}_) of each source. This work also aims at testing the latest generation of BT-SETTL atmospheric models. We estimated spectral types using spectral indices and spectra of reference young objects classified in the optical. We used the 2010 and 2012 releases of the BT-SETTL synthetic spectral grid and cross-checked the results with the DRIFT-PHOENIX models to derive the atmospheric properties of the sources.
