- ID:
- ivo://CDS.VizieR/J/ApJ/899/14
- Title:
- Optical & FeII sources in Supernova remnant with HST
- Short Name:
- J/ApJ/899/14
- Date:
- 14 Mar 2022 07:07:21
- Publisher:
- CDS
- Description:
- NGC6946 is a high-star-formation-rate, face-on, spiral galaxy that has hosted 10 supernovae since 1917. Not surprisingly, a large number of supernova remnants and candidates have been identified either as optical nebulae with high [SII]:H{alpha} line ratios (147) or as compact non-thermal radio sources (35). However, there are only seven overlaps between these two samples. Here, we apply [FeII] 1.644{mu}m emission as a new diagnostic to search for supernova remnants in an attempt to resolve this discrepancy. [FeII] is expected to be relatively strong in the radiative shocks of supernova remnants and almost absent in HII regions. It is less susceptible to the effects of absorption along the line of sight than the optical lines normally used to identify remnants. Using data from the WFC3 camera on Hubble Space Telescope (HST), we identify 132 [FeII] emission nebulae in NGC6946 as likely supernova remnants. Of these, 54 align with previously known optical supernova remnants. The remaining 78 objects are new; of these 44 are visible in new HST imagery in H{alpha} and [SII]. This brings the total number of supernova remnant candidates (from optical and/or IR data) in NGC6946 to 225. A total of 14 coincidences with radio supernova remnant candidates (out of 30 in our search area) are found in this expanded list. The identification of so many new remnant candidates validates the use of [FeII] imagery for finding remnants, and suggests that previous remnant searches in other galaxies may be far from complete.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/334
- Title:
- Optical/MIR properties of Type 1 AGNs
- Short Name:
- J/MNRAS/472/334
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigated the connection between the mid-infrared (MIR) and optical spectral characteristics in a sample of 82 Type 1 active galactic nuclei (AGNs), observed with Infrared Spectrometer on Spitzer (IRS) and Sloan Digital Sky Survey (SDSS, DR12). We found several interesting correlations between optical and MIR spectral properties: (i) as starburst significators in MIR increase, the equivalent widths (EWs) of optical lines H{beta}NLR and FeII, increase as well; (ii) as MIR spectral index increases, EW([OIII]) decreases, while fractional contribution of AGN (RAGN) is not connected with EW([OIII]); (iii) The log([OIII]5007/H{beta}NLR) ratio is weakly related to the fractional contribution of polycyclic aromatic hydrocarbons (RPAHs). We compare the two different MIR and optical diagnostics for starburst contribution to the overall radiation (RPAH and Baldwin, Philips & Terlevich diagram, respectively). The significant differences between optical and MIR starburst diagnostics were found. The starburst influence to observed correlations between optical and MIR parameters is discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/431/779
- Title:
- Optical/near-IR atlas of OH/IR stars
- Short Name:
- J/A+A/431/779
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present optical and near-infrared finding charts, accurate astrometry (~1") and single-epoch near-infrared photometry for 371 IRAS sources, 96% of those included in the so-called "Arecibo sample of OH/IR stars" (Eder et al., 1988ApJS...66..183E; Lewis et al., 1990ApJ...362..634L; Chengalur et al., 1993, Cat. <J/ApJS/89/189>). The main photometric properties of the stars in the sample are presented and discussed as well as the problems found during the process of identification of the optical/near-infrared counterparts. In addition, we also identify suitable reference stars in each field to be used for differential photometry purposes in the future.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/679
- Title:
- Optical spectroscopy in Cygnus X region
- Short Name:
- J/ApJ/720/679
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new images and photometry of the massive star-forming complex Cygnus X obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS) on board the Spitzer Space Telescope. A combination of IRAC, MIPS, UKIRT Deep Infrared Sky Survey, and Two Micron All Sky Survey data are used to identify and classify young stellar objects (YSOs). Of the 8231 sources detected exhibiting infrared excess in Cygnus X North, 670 are classified as class I and 7249 are classified as class II. Using spectra from the FAST Spectrograph at the Fred L. Whipple Observatory and Hectospec on the MMT, we spectrally typed 536 sources in the Cygnus X complex to identify the massive stars. We find that YSOs tend to be grouped in the neighborhoods of massive B stars (spectral types B0 to B9).
- ID:
- ivo://CDS.VizieR/J/A+A/458/173
- Title:
- Optical spectroscopy of 253 IRAS sources
- Short Name:
- J/A+A/458/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the optical spectral properties of a sample of stars showing far infrared colours similar to those of well-known planetary nebulae. The large majority of them were unidentified sources or poorly known in the literature at the time when this spectroscopic survey started, some 15 years ago. We present low-resolution optical spectroscopy, finding charts and improved astrometric coordinates of a sample of 253 IRAS sources.
- ID:
- ivo://CDS.VizieR/J/A+A/306/924
- Title:
- Optical spectrum of HR 4049
- Short Name:
- J/A+A/306/924
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution optical spectra (UES/WHT) of the extreme metal-poor post-AGB star HR 4049 were obtained at four different orbital phases. The spectra cover the wavelength region from 3650A to 10850A at a resolution of R=5.2x10^4^. These observations are supplemented with four high-resolution spectra of the NaI D1 & D2 and CaII K lines at R=~10^5^ (CAT/CES). The optical spectrum shows 217 spectral lines: the Balmer series (H{alpha} - H35), the Paschen series (P9 - P23), NI, OI and numerous CI lines. We show that the lines of H{alpha}, H{beta}, H{gamma} and NaI D show significant changes in profile between different observation dates. Nine components were identified in the profile of the NaI D lines of which three are circumstellar and six interstellar. The stronger CI lines are asymmetric and we derive a post-AGB mass-loss of {dot}(M)=6+/-4x10^-7^M_{sun}_/yr from the asymmetry. The [OI]6300A line has been detected in emission at the system velocity and we argue that the emission is from an almost edge-on disk with a radius of about 20R_*_. HR 4049 is at J2000 position: 00 42 45.8 - 20 21 36
- ID:
- ivo://CDS.VizieR/J/ApJ/835/274
- Title:
- Optical to NIR spectra of nova V2676 Oph 2012
- Short Name:
- J/ApJ/835/274
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical spectrophotometric and near-infrared (NIR) photometric observations of the nova V2676 Oph covering the period from 2012 March 29 through 2015 May 8. The optical spectra and photometry of the nova have been taken from SMARTS and Asiago; the NIR photometry was obtained from SMARTS and Mt. Abu. The spectra were dominated by strong H I lines from the Balmer series, FeII, NI, and [OI] lines in the initial days, typical of an Fe II type nova. The measured FWHM for the H{beta} and H{alpha} lines was 800-1200km/s. There was pronounced dust formation starting 90 days after the outburst. The J-K color was the largest among recent dust-forming novae.
- ID:
- ivo://CDS.VizieR/J/ApJS/238/37
- Title:
- Opt. & NIR spectral atlas of 16 2MASS NIR-red AGNs
- Short Name:
- J/ApJS/238/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present medium-resolution spectra (R~2000-4000) at 0.4-1.0{mu}m and 0.7-2.5{mu}m of 16 active galactic nuclei (AGNs) selected with red color in the near-infrared (NIR) of J-K>2.0mag at z~0.3. We fit the H{beta}, H{alpha}, P{beta}, and P{alpha} lines from these spectra to obtain their luminosities and line widths. We derive the E(B-V) color excess values of the NIR-red AGNs using two methods, one based on the line-luminosity ratios and another based on the continuum slopes. The two E(B-V) values agree with each other at rms dispersion ~0.249. About half of the NIR-red AGNs have g'-K<5 magnitude, and we find that these NIR-red, but blue in optical-NIR AGNs, have E(B-V)~0, suggesting that a significant fraction of the NIR color-selected red AGNs are unobscured or only mildly obscured. After correcting for the dust extinction, we estimate the black hole (BH) masses and the bolometric luminosities of the NIR-red AGNs using the Paschen lines to calculate their Eddington ratios ({lambda}Edd). The median Eddington ratios of nine NIR-red AGNs (log({lambda}_Edd_~-0.654+/-0.176) are only mildly higher than those of unobscured type 1 AGNs (log({lambda}_Edd_~-0.961+/-0.008). Moreover, we find that the MBH-{sigma}* relation for three NIR-red AGNs is consistent with that of unobscured type 1 AGNs at similar redshift. These results suggest that the NIR-red color selection alone is not effective at picking up dusty, intermediate-stage AGNs.
- ID:
- ivo://CDS.VizieR/J/ApJ/854/145
- Title:
- Opt. photometry & NIR spectroscopy of Wolf 1130
- Short Name:
- J/ApJ/854/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following the discovery of the T8 subdwarf WISE J200520.38+542433.9 (Wolf 1130C), which has a proper motion in common with a binary (Wolf 1130AB) consisting of an M subdwarf and a white dwarf, we set out to learn more about the old binary in the system. We find that the A and B components of Wolf 1130 are tidally locked, which is revealed by the coherence of more than a year of V-band photometry phase-folded to the derived orbital period of 0.4967 days. Forty new high-resolution, near-infrared spectra obtained with the Immersion Grating Infrared Spectrometer (IGRINS) provide radial velocities and a projected rotational velocity (vsini) of 14.7+/-0.7km/s for the M subdwarf. In tandem with a Gaia parallax-derived radius and verified tidal locking, we calculate an inclination of i=29{deg}+/-2{deg}. From the single-lined orbital solution and the inclination we derive an absolute mass for the unseen primary (1.24_-0.15_^+0.19^M_{sun}_). Its non-detection between 0.2 and 2.5{mu}m implies that it is an old (>3.7Gyr) and cool (T_eff_<7000K) ONe white dwarf. This is the first ultramassive white dwarf within 25pc. The evolution of Wolf 1130AB into a cataclysmic variable is inevitable, making it a potential SN Ia progenitor. The formation of a triple system with a primary mass >100 times the tertiary mass and the survival of the system through the common-envelope phase, where ~80% of the system mass was lost, is remarkable. Our analysis of Wolf 1130 allows us to infer its formation and evolutionary history, which has unique implications for understanding low-mass star and brown dwarf formation around intermediate-mass stars.
- ID:
- ivo://CDS.VizieR/J/AJ/160/58
- Title:
- Orbits of spectro. binaries with CHARA Array. III.
- Short Name:
- J/AJ/160/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the visual orbits of two long-period spectroscopic binary stars, HD8374 and HD24546, using interferometric observations acquired with the Center for High Angular Resolution Astronomy (CHARA) Array and the Palomar Testbed Interferometer. We also obtained new radial velocities from echelle spectra using the APO 3.5m and Fairborn 2.0 telescopes. By combining the visual and spectroscopic observations, we solve for the full, three-dimensional orbits and determine the stellar masses and distances to within 3% uncertainty. We then estimate the effective temperature and radius of each component star through Doppler tomography and spectral energy distribution analyses, in order to compare the observed stellar parameters to the predictions of stellar evolution models. For HD8374, we find masses of M1=1.636{+/-}0.050M{sun} and M2=1.587{+/-}0.049M{sun}, radii of R1=1.84{+/-}0.05R{sun} and R2=1.66{+/-}0.12R{sun}, temperatures of Teff_1_=7280{+/-}110K and Teff-2-=7280{+/-}120K, and an estimated age of 1.0Gyr. For HD24546, we find masses of M1=1.434{+/-}0.014M{sun} and M2=1.409{+/-}0.014M{sun}, radii of R_1_=1.67{+/-}0.06R{sun} and R_2_=1.60{+/-}0.10R{sun}, temperatures of Teff_1_=6790{+/-}120K and Teff_2_=6770{+/-}90K, and an estimated age of 1.4Gyr. HD24546 is therefore too old to be a member of the Hyades cluster, despite its physical proximity to the group.
