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791. FLAMES observations of NGC 5128's globular clusters
ID:
ivo://CDS.VizieR/J/ApJ/805/65
Title:
FLAMES observations of NGC 5128's globular clusters
Short Name:
J/ApJ/805/65
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of the dynamical properties of 125 compact stellar systems (CSSs) in the nearby giant elliptical galaxy NGC 5128, using high-resolution spectra (R~26000) obtained with Very Large Telescope/FLAMES. Our results provide evidence for a new type of star cluster, based on the CSS dynamical mass scaling relations. All radial velocity (v_r_) and line-of-sight velocity dispersion ({sigma}_los_) measurements are performed with the penalized pixel fitting (ppxf) technique, which provided {sigma}_ppxf_ estimates for 115 targets. The {sigma}_ppxf_ estimates are corrected to the 2D projected half-light radii, {sigma}_1/2_, as well as the cluster cores, {sigma}_0_, accounting for observational/aperture effects and are combined with structural parameters, from high spatial resolution imaging, in order to derive total dynamical masses (M_dyn_) for 112 members of NGC5128's star cluster system. In total, 89 CSSs have dynamical masses measured for the first time along with the corresponding dynamical mass-to-light ratios ({sigma}_1/2_). We find two distinct sequences in the {gamma}^dyn^_V_-M_dyn_ plane, which are well approximated by power laws of the forms {gamma}^dyn^_V_{propto}M_dyn_^0.33+/-0.04^ and {gamma}^dyn^_V_{propto}M_dyn_^0.79+/-0.04^. The shallower sequence corresponds to the very bright tail of the globular cluster luminosity function (GCLF), while the steeper relation appears to be populated by a distinct group of objects that require significant dark gravitating components such as central massive black holes and/or exotically concentrated dark matter distributions. This result would suggest that the formation and evolution of these CSSs are markedly different from the "classical" globular clusters in NGC 5128 and the Local Group, despite the fact that these clusters have luminosities similar to the GCLF turnover magnitude. We include a thorough discussion of myriad factors potentially influencing our measurements.
792. Flash/Heros Split-Order SSAP Service
ID:
ivo://org.gavo.dc/flashheros/q/echssa
Title:
Flash/Heros Split-Order SSAP Service
Short Name:
F/H Orders SSAP
Date:
27 Dec 2024 08:31:06
Publisher:
The GAVO DC team
Description:
Spectra from the Flash and Heros Echelle spectrographs developed at Landessternwarte Heidelberg and mounted at La Silla and various other observatories. The data mostly contains spectra of OB stars. Heros was the name of the instrument after Flash got a second channel in 1995.
793. Flash/Heros SSAP
ID:
ivo://org.gavo.dc/flashheros/q/ssa
Title:
Flash/Heros SSAP
Short Name:
Flash/Heros SSAP
Date:
27 Dec 2024 08:31:06
Publisher:
The GAVO DC team
Description:
Spectra from the Flash and Heros Echelle spectrographs developed at Landessternwarte Heidelberg and mounted at La Silla and various other observatories. The data mostly contains spectra of OB stars. Heros was the name of the instrument after Flash got a second channel in 1995.
794. Fluorescence excitation models in comets
ID:
ivo://CDS.VizieR/J/ApJ/727/91
Title:
Fluorescence excitation models in comets
Short Name:
J/ApJ/727/91
Date:
21 Oct 2021
Publisher:
CDS
Description:
Ammonia is a major reservoir of nitrogen atoms in cometary materials. However, detections of ammonia in comets are rare, with several achieved at radio wavelengths. A few more detections were obtained through near-infrared observations (around the 3um wavelength region), but moderate relative velocity shifts are required to separate emission lines of cometary ammonia from telluric absorption lines in the 3um wavelength region. On the other hand, the amidogen radical (NH_2_, a photodissociation product of ammonia in the coma) also shows rovibrational emission lines in the 3um wavelength region. Thus, gas production rates for ammonia can be determined from the rovibrational emission lines of ammonia (directly) and amidogen radical (indirectly) simultaneously in the near-infrared. In this article, we present new fluorescence excitation models for cometary ammonia and amidogen radical in the near-infrared, and we apply these models to the near-infrared high-dispersion spectra of comet C/2004 Q2 (Machholz) to determine the mixing ratio of ammonia to water in the comet. Based on direct detection of NH_3_ lines, the mixing ratio of NH_3_/H_2_O is 0.46%+/-0.03% in C/2004 Q2 (Machholz), in agreement with other results. The mixing ratio of ammonia determined from the NH_2_ observations (0.31%-0.79%) is consistent but has relatively larger error, owing to uncertainty in the photodissociation rates of ammonia. At the present level of accuracy, we confirm that NH_3_ could be the sole parent of NH_2_ in this comet.
795. Fluorescent H_2_ emission from T Tauri stars
ID:
ivo://CDS.VizieR/J/ApJS/165/256
Title:
Fluorescent H_2_ emission from T Tauri stars
Short Name:
J/ApJS/165/256
Date:
21 Oct 2021
Publisher:
CDS
Description:
We survey fluorescent H2 emission in HST STIS spectra of the classical T Tauri stars (CTTSs) TW Hya, DF Tau, RU Lupi, T Tau, and DG Tau, and the weak-lined T Tauri star (WTTS) V836 Tau. From each of those sources we detect between 41 and 209 narrow H_2_ emission lines, most of which are pumped by strong Ly{alpha} emission. H_2_ emission is not detected from the WTTS V410 Tau. The fluorescent H_2_ emission appears to be common to circumstellar environments around all CTTSs, but high spectral and spatial resolution STIS observations reveal diverse phenomenon.
796. Flux conversion factors for the Swift/UVOT filters
ID:
ivo://CDS.VizieR/J/AJ/152/102
Title:
Flux conversion factors for the Swift/UVOT filters
Short Name:
J/AJ/152/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
We discuss the transformation of observed photometry into flux for the creation of spectral energy distributions (SED) and the computation of bolometric luminosities. We do this in the context of supernova studies, particularly as observed with the Swift spacecraft, but the concepts and techniques should be applicable to many other types of sources and wavelength regimes. Traditional methods of converting observed magnitudes to flux densities are not very accurate when applied to UV photometry. Common methods for extinction and the integration of pseudo-bolometric fluxes can also lead to inaccurate results. The sources of inaccuracy, though, also apply to other wavelengths. Because of the complicated nature of translating broadband photometry into monochromatic flux densities, comparison between observed photometry and a spectroscopic model is best done by forward modeling the spectrum into the count rates or magnitudes of the observations. We recommend that integrated flux measurements be made using a spectrum or SED which is consistent with the multi-band photometry rather than converting individual photometric measurements to flux densities, linearly interpolating between the points, and integrating. We also highlight some specific areas where the UV flux can be mischaracterized.
797. Fluxes and abundances of PNe in M33
ID:
ivo://CDS.VizieR/J/ApJ/696/729
Title:
Fluxes and abundances of PNe in M33
Short Name:
J/ApJ/696/729
Date:
21 Oct 2021
Publisher:
CDS
Description:
The planetary nebula (PN) population of M33 is studied via multifiber spectroscopy with Hectospec at the MMT. In this paper, we present the spectra of 102 PNe, whereas plasma diagnostic and chemical abundances were performed on the 93 PNe where the necessary diagnostic lines were measured. About 20% of the PNe are compatible with being Type I; the rest of the sample is the progeny of an old disk stellar population, with main sequence masses M<3M_{sun}_ and ages t>0.3Gyr. Our observations do not seem to imply that the metallicity gradient across the M33 disk has flattened considerably with time. We report also the discovery of a PN with Wolf-Rayet features, PN039, belonging the class of late [WC] stars.
798. Fluxes of NGG7793 & NGC4945 with GMOS-S
ID:
ivo://CDS.VizieR/J/ApJ/812/39
Title:
Fluxes of NGG7793 & NGC4945 with GMOS-S
Short Name:
J/ApJ/812/39
Date:
21 Oct 2021
Publisher:
CDS
Description:
Gas-phase abundances in HII regions of two spiral galaxies, NGC7793 and NGC4945, have been studied to determine their radial metallicity gradients. We used the strong-line method to derive oxygen abundances from spectra acquired with GMOS-S, the multi-object spectrograph on the 8m Gemini South telescope. We found that NGC7793 has a well-defined gas-phase radial oxygen gradient of -0.321+/-0.112dexR_25_^-1^ (or -0.054+/-0.019dex/kpc) in the galactocentric range 0.17<R_G_/R_25_<0.82, not dissimilar from gradients calculated with direct abundance methods in galaxies of similar mass and morphology. We also determined a shallow radial oxygen gradient in NGC 4945, -0.253+/-0.149dexR_25_^-1^ (or -0.019+/-0.011dex/kpc) for 0.04<R_G_/R_25_<0.51, where the larger relative uncertainty derives mostly from the larger inclination of this galaxy. NGC 7793 and NGC 4945 have been selected for this study because they are similar, in mass and morphology, to M33 and the Milky Way, respectively. Since at zeroth order we expect the radial metallicity gradients to depend on mass and galaxy type, we compared our galaxies in the framework of radial metallicity models best suited for M33 and the Galaxy. We found a good agreement between M33 and NGC7793, pointing toward similar evolution for the two galaxies. We notice instead differences between NGC 4945 and the radial metallicity gradient model that best fits the Milky Way. We found that these differences are likely related to the presence of an active galactic nucleus combined with a bar in the central regions of NGC 4945, and to its interacting environment.
799. FMOS-COSMOS survey III. 0.7<z<2.5 galaxies
ID:
ivo://CDS.VizieR/J/ApJS/220/12
Title:
FMOS-COSMOS survey III. 0.7<z<2.5 galaxies
Short Name:
J/ApJS/220/12
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a spectroscopic survey of galaxies in the COSMOS field using the Fiber Multi-object Spectrograph (FMOS), a near-infrared instrument on the Subaru Telescope. Our survey is specifically designed to detect the H{alpha} emission line that falls within the H-band (1.6-1.8{mu}m) spectroscopic window from star-forming galaxies with 1.4<z<1.7 and M_stellar_>~10^10^M_{sun}_. With the high multiplex capability of FMOS, it is now feasible to construct samples of over 1000 galaxies having spectroscopic redshifts at epochs that were previously challenging. The high-resolution mode (R~2600) effectively separates H{alpha} and [NII]{lambda}6585, thus enabling studies of the gas-phase metallicity and photoionization state of the interstellar medium. The primary aim of our program is to establish how star formation depends on stellar mass and environment, both recognized as drivers of galaxy evolution at lower redshifts. In addition to the main galaxy sample, our target selection places priority on those detected in the far-infrared by Herschel/PACS to assess the level of obscured star formation and investigate, in detail, outliers from the star formation rate (SFR)--stellar mass relation. Galaxies with H{alpha} detections are followed up with FMOS observations at shorter wavelengths using the J-long (1.11-1.35{mu}m) grating to detect H{beta} and [OIII]{lambda}5008 which provides an assessment of the extinction required to measure SFRs not hampered by dust, and an indication of embedded active galactic nuclei. With 460 redshifts measured from 1153 spectra, we assess the performance of the instrument with respect to achieving our goals, discuss inherent biases in the sample, and detail the emission-line properties. Our higher-level data products, including catalogs and spectra, are available to the community.
800. Follow-up observations of SNIa ASASSN-14lp
ID:
ivo://CDS.VizieR/J/ApJ/826/144
Title:
Follow-up observations of SNIa ASASSN-14lp
Short Name:
J/ApJ/826/144
Date:
21 Oct 2021
Publisher:
CDS
Description:
On 2014 December 9.61, the All-sky Automated Survey for SuperNovae (ASAS-SN or "Assassin") discovered ASASSN-14lp just ~2 days after first light using a global array of 14cm diameter telescopes. ASASSN-14lp went on to become a bright supernova (V=11.94mag), second only to SN 2014J for the year. We present prediscovery photometry (with a detection less than a day after first light) and ultraviolet through near-infrared photometric and spectroscopic data covering the rise and fall of ASASSN-14lp for more than 100 days. We find that ASASSN-14lp had a broad light curve ({Delta}m_15_(B)=0.80+/-0.05), a B-band maximum at 2457015.82+/-0.03, a rise time of 16.94_-0.10_^+0.11^days, and moderate host-galaxy extinction (E(B-V)_host_=0.33+/-0.06). Using ASASSN-14lp, we derive a distance modulus for NGC 4666 of {mu}=30.8+/-0.2, corresponding to a distance of 14.7+/-1.5Mpc. However, adding ASASSN-14lp to the calibrating sample of Type Ia supernovae still requires an independent distance to the host galaxy. Finally, using our early-time photometric and spectroscopic observations, we rule out red giant secondaries and, assuming a favorable viewing angle and explosion time, any nondegenerate companion larger than 0.34R_{sun}_.

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