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701. Mid-infrared diameter of W Hya
ID:
ivo://CDS.VizieR/J/A+A/530/A120
Title:
Mid-infrared diameter of W Hya
Short Name:
J/A+A/530/A120
Date:
21 Oct 2021
Publisher:
CDS
Description:
Mid-infrared (N-band) interferometric data of W Hya were obtained with MIDI/VLTI between April 2007 and September 2009, covering nearly three pulsation cycles. The spectrally dispersed visibility data of all 75 observations were analyzed by fitting a circular fully limb-darkened disk (FDD) model to all data and individual pulsation phases. Asymmetries were studied with an elliptical FDD. Modeling results in an apparent angular FDD diameter of W Hya of about (80+/-1.2)mas (7.8AU) between 8 and 10 micron, which corresponds to an about 1.9 times larger diameter than the photospheric one. The diameter gradually increases up to (105+/-1.2)mas (10.3AU) at 12 micron. In contrast, the FDD relative flux fraction decreases from (0.85+/-0.02) to (0.77+/-0.02), reflecting the increased flux contribution from a fully resolved surrounding silicate dust shell. The asymmetric character of the extended structure could be confirmed. An elliptical FDD yields a position angle of (11+/-20)deg and an axis ratio of (0.87+/-0.07). A weak pulsation dependency is revealed with a diameter increase of (5.4+/-1.8)mas between visual minimum and maximum, while detected cycle-to-cycle variations are smaller.
702. Mid-infrared images of W75N
ID:
ivo://CDS.VizieR/J/A+A/445/971
Title:
Mid-infrared images of W75N
Short Name:
J/A+A/445/971
Date:
21 Oct 2021
Publisher:
CDS
Description:
An infrared study that includes ground-based mid-infrared images between 8.7 and 18.7um and IRAC images at 3.6, 4.5, 5.8 and 8.0um of the W75 N massive star forming region is presented. The 12.5um image shows the presence of four mid-infrared sources in the region W75 N(B), three of which have bright near-infrared counterparts, IRS 1, IRS 2 and IRS 3, all with significant excess emission at lambda>2.0um. IRS 2 has a steep energy distribution and the computed infrared luminosity is consistent with the presence of a young B3 star. The observed IRAC colors of IRS 3 indicate that this source is a Class II intermediate mass young star, consistent with its infrared energy distribution and luminosity. The fourth, newly discovered, mid-infrared source appears coincident with the ultracompact HII region VLA 3, and is located within the millimeter core MM 1. We derived a luminosity of ~750L_{sun}_ and a visual extinction A_V_~90 for this source. From the IRAC images, we detected 75 sources in an area of 120"x120" centered in W75 N. At least 25 of these sources are associated with the molecular cloud and form a young stellar cluster as shown in the IRAC two-color and the H-Ks versus Ks-[3.6] diagrams.
703. Mid-infrared spectral variability atlas of YSOs
ID:
ivo://CDS.VizieR/J/ApJS/201/11
Title:
Mid-infrared spectral variability atlas of YSOs
Short Name:
J/ApJS/201/11
Date:
21 Oct 2021
Publisher:
CDS
Description:
The atlas presents medium-resolution mid-infrared spectra of low- and intermediate mass pre-main sequence objects obtained by the ISOPHOT-S spectrophotometer of the Infrared Space Observatory (ISO) and the Infrared Spectrograph (IRS) of the Spitzer Space Telescope.
704. Mid-IR and radio interferometry of S Ori
ID:
ivo://CDS.VizieR/J/A+A/470/191
Title:
Mid-IR and radio interferometry of S Ori
Short Name:
J/A+A/470/191
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first multi-epoch study that includes concurrent mid-infrared and radio interferometry of an oxygen-rich Mira star. We obtained mid-infrared interferometry of S Ori with VLTI/MIDI at four epochs in December 2004, February/March 2005, November 2005, and December 2005. We concurrently observed v=1, J=1-0 (43.1GHz) and v=2, J=1-0 (42.8GHz) SiO maser emission toward S Ori with the VLBA in January, February, and November 2005. The MIDI data are analyzed using self-excited dynamic model atmospheres including molecular layers, complemented by a radiative transfer model of the circumstellar dust shell. The VLBA data are reduced to the spatial structure and kinematics of the maser spots. The modeling of our MIDI data results in phase-dependent continuum photospheric angular diameters of 9.0+/-0.3mas (phase 0.42), 7.9+/-0.1mas (0.55), 9.7+/-0.1mas (1.16), and 9.5+/-0.4mas (1.27). The dust shell can best be modeled with Al2O3 grains alone using phase-dependent inner boundary radii between 1.8 and 2.4 photospheric radii. The dust shell appears to be more compact with larger optical depth near visual minimum (tau_V_~2.5), and more extended with lower optical depth after visual maximum (tau_V_~1.5). The ratios of the 43.1GHz/42.8GHz SiO maser ring radii to the photospheric radii are 2.2+/-0.3/2.1+/-0.2 (phase 0.44), 2.4+/-0.3/2.3+/-0.4 (0.55), and 2.1+/-0.3/1.9+/-0.2 (1.15). The maser spots mark the region of the molecular atmospheric layers shortly outward of the steepest decrease of the mid-infrared model intensity profile. Their velocity structure indicates a radial gas expansion. S Ori shows significant phase-dependences of photospheric radii and dust shell parameters. Al2O3 dust grains and SiO maser spots form at relatively small radii of ~1.8-2.4 photospheric radii. Our results suggest increased mass-loss and dust formation close to the surface near minimum visual phase, when Al2O3 dust grains are co-located with the molecular gas and the SiO maser shells, and a more expanded dust shell after visual maximum. Silicon does not appear to be bound in dust, as our data shows no sign of silicate grains.
705. Mid-IR content of BGPS sources
ID:
ivo://CDS.VizieR/J/ApJ/731/90
Title:
Mid-IR content of BGPS sources
Short Name:
J/ApJ/731/90
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a search for mid-infrared signs of star formation activity in the 1.1mm sources in the Bolocam Galactic Plane Survey (BGPS). We have correlated the BGPS catalog (Cat. J/ApJS/188/123) with available mid-IR Galactic plane catalogs based on the Spitzer Space Telescope GLIMPSE legacy survey (including Cat. J/AJ/136/2413 and the EGO cat. J/AJ/136/2391) and the Midcourse Space Experiment (MSX) Galactic plane survey (RMS catalog, Hoare et al. 2004ASPC..317..156H). We find that 44% (3712 of 8358) of the BGPS sources contain at least one mid-IR source, including 2457 of 5067 (49%) within the area where all surveys overlap (10{deg}<l<65{deg}). Accounting for chance alignments between the BGPS and mid-IR sources, we conservatively estimate that 20% of the BPGS sources within the area where all surveys overlap show signs of active star formation. We separate the BGPS sources into four groups based on their probability of star formation activity. Extended Green Objects and Red MSX Sources make up the highest probability group, while the lowest probability group is comprised of "starless" BGPS sources which were not matched to any mid-IR sources. The mean 1.1mm flux of each group increases with increasing probability of active star formation.
706. Mid-IR emission lines in AGNs
ID:
ivo://CDS.VizieR/J/ApJ/725/2270
Title:
Mid-IR emission lines in AGNs
Short Name:
J/ApJ/725/2270
Date:
21 Oct 2021
Publisher:
CDS
Description:
We used Spitzer/Infrared Spectrograph spectroscopic data on 426 galaxies including quasars, Seyferts, LINERs, and HII galaxies to investigate the relationship among the mid-IR emission lines. There is a tight linear correlation between the [NeV]14.3um and 24.3um (97.1eV) and the [OIV]25.9um (54.9eV) high-ionization emission lines. The correlation also holds for these high-ionization emission lines and the [NeIII]15.56um (41eV) emission line, although only for active galaxies. We used these correlations to calculate the [NeIII] excess due to star formation in Seyfert galaxies. We also estimated the [OIV] luminosity due to star formation in active galaxies and determined that it dominates the [OIV] emission only if the contribution of the active nucleus to the total luminosity is below 5%. We find that the active galactic nucleus dominates the [OIV] emission in most Seyfert galaxies, whereas star formation adequately explains the observed [OIV] emission in optically classified HII galaxies. Finally, we computed photoionization models to determine the physical conditions of the narrow-line region where these high-ionization lines originate. The estimated ionization parameter range is -2.8<logU<-2.5 and the total hydrogen column density range is 20<logn_H_(cm^-2^)<21.
707. Mid-IR imaging in {rho} Oph
ID:
ivo://CDS.VizieR/J/ApJ/630/381
Title:
Mid-IR imaging in {rho} Oph
Short Name:
J/ApJ/630/381
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results of a comprehensive, new, ground-based mid-infrared imaging survey of the young stellar population of the {rho} Ophiuchi cloud are presented. Data were acquired at the Palomar 5m and at the Keck 10m telescopes with the MIRLIN (Mid-InfraRed Large-well Imager) and LWS (Long Wavelength Spectrometer centered at 12.5{mu}m) instruments, at 0.5" and 0.25" resolutions, respectively. Of 172 survey objects, 85 were detected. Among the 22 multiple systems observed, 15 were resolved and their individual component fluxes determined.
708. Mid-IR indicators of SF and AGN in galaxies
ID:
ivo://CDS.VizieR/J/ApJ/719/1191
Title:
Mid-IR indicators of SF and AGN in galaxies
Short Name:
J/ApJ/719/1191
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the use of mid-infrared (MIR) polycyclic aromatic hydrocarbon (PAH) bands, the continuum, and emission lines as probes of star formation (SF) and active galactic nucleus (AGN) activity in a sample of 100 "normal" and local (z~0.1) emission-line galaxies. The MIR spectra were obtained with the Spitzer Space Telescope Infrared Spectrograph as part of the Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS), which includes multi-wavelength photometry from the ultraviolet to the far-infrared and optical spectroscopy. The continuum and features were extracted using PAHFIT, a decomposition code which we find to yield PAH equivalent widths (EWs) up to ~30 times larger than the commonly used spline methods. Despite the lack of extreme objects in our sample (such as strong AGNs, low-metallicity galaxies, or ULIRGs), we find significant variations in PAH, continuum, and emission-line properties, and systematic trends between these MIR properties and optically derived physical properties, such as age, metallicity, and radiation field hardness. We revisit the diagnostic diagram relating PAH EWs and [NeII]12.8um/[OIV]25.9um line ratios and find it to be in much better agreement with the standard optical SF/AGN classification than when spline decompositions are used, while also potentially revealing obscured AGNs.
709. Mid-IR photometry in the Orion Nebula
ID:
ivo://CDS.VizieR/J/AJ/129/1534
Title:
Mid-IR photometry in the Orion Nebula
Short Name:
J/AJ/129/1534
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present two wide-field (~5'x3.5'), diffraction-limited ({lambda}/D~0.5" at 10{mu}m), broadband 10 and 20{mu}m images of the Orion Nebula, plus six 7-13{mu}m narrowband images of the BN/KL complex taken at the 3.8m UKIRT telescope with the MPIA MAX camera.
710. Mid-IR properties of GOALS nearby LIRGs
ID:
ivo://CDS.VizieR/J/ApJS/206/1
Title:
Mid-IR properties of GOALS nearby LIRGs
Short Name:
J/ApJS/206/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Great Observatories All-Sky LIRG Survey (GOALS, Armus et al. 2009PASP..121..559A) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here we present low resolution Spitzer Infrared Spectrograph spectra covering 5-38um and provide a basic analysis of the mid-IR spectral properties observed for nearby LIRGs. In a companion paper, we discuss detailed fits to the spectra and compare the LIRGs to other classes of galaxies. The GOALS sample of 244 nuclei in 180 luminous (10^11^<=L_IR_/L_{sun}_<10^12^) and 22 ultraluminous (L_IR_/L_{sun}_>=10^12^) IR galaxies represents a complete subset of the IRAS Revised Bright Galaxy Sample (Sanders, 2003, Cat. J/AJ/126/1607) and covers a range of merger stages, morphologies, and spectral types. The majority (>60%) of the GOALS LIRGs have high 6.2um polycyclic aromatic hydrocarbon (PAH) equivalent widths (EQW_6.2um_>0.4um) and low levels of silicate absorption (s_9.7um_>-1.0).