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- ID:
- ivo://CDS.VizieR/J/A+A/588/A63
- Title:
- Photometry of DBS 77-78-102-160-161 regions
- Short Name:
- J/A+A/588/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a study of the global properties of some embedded clusters placed in the fourth quadrant of the MilkyWay to clarify some issues related with their location into de Galaxy and their stellar formation processes. We performed BVI photometric observations in the region of DBS 77, 78, 102, 160, and 161 clusters and infrared spectroscopy in DBS 77 region. They were complemented with JHK data from VVV survey combined with 2MASS catalogue, and used mid-infrared information from GLIMPSE catalogue. We also searched for HI data from SGPS and PMN radio surveys, and previous spectroscopic stellar classification. The spectroscopic and photometric information allowed us to estimate the spectral classification of the brightest stars of each studied region. On the other hand, we used the radio data to investigate the interstellar material parameters and the continuum sources probably associated with the respective stellar components. We estimated the basic physical parameters of the clusters (reddening, distance, age, and initial mass function). We searched for HII regions located near to the studied clusters and we analyzed the possible link between them. In the particular case of DBS 160-161 clusters, we identified the HI bubble B332.5-0.1-42 located around them. We found that the mechanical energy injected to the interstellar medium by the more massive stars of this couple of clusters was enough to generate the bubble.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A99
- Title:
- Photometry of EXors from Asiago plates
- Short Name:
- J/A+A/602/A99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- EXor objects are young variables that show episodic variations of brightness commonly associated to enhanced accretion outbursts. With the aim of investigating the long-term photometric behaviour of a few EXor sources, we present here data from the archival plates of the Asiago Observatory, showing the Orion field where the three EXors V1118, V1143, and NY are located. A total of 484 plates were investigated, providing a total of more than 1000 magnitudes for the three stars, which cover a period of about 35yrs between 1959 to 1993. We then compared our data with literature data. Apart from a newly discovered flare-up of V1118, we identify the same outbursts already known, but we provide two added values: (i) a long-term sampling of the quiescence phase; and (ii) repeated multi-colour observations (BVRI bands). The former allows us to give a reliable characterisation of the quiescence, which represents a unique reference for studies that will analyze future outbursts and the physical changes induced by these events. The latter is useful for confirming whether the intermittent increases of brightness are accretion-driven (as in the case of V1118), or extinction-driven (as in the case of V1143). Accordingly, doubts arise about the V1143 classification as a pure EXor object. Finally, although our plates do not separate NY Ori and the star very close to it, they indicate that this EXor did not undergo any major outbursts during our 40yrs of monitoring.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/65
- Title:
- Photometry of LBGs, LAEs and GNBs at z~2.85
- Short Name:
- J/ApJ/779/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a survey for z~2.85 Lyman-continuum (LyC) emission in the HS1549+1933 field and place constraints on the amount of ionizing radiation escaping from star-forming galaxies. Using a custom narrowband filter (NB3420) tuned to wavelengths just below the Lyman limit at z>=2.82, we probe the LyC spectral region of 49 Lyman break galaxies (LBGs) and 91 Ly{alpha} emitters (LAEs) spectroscopically confirmed at z>=2.82. Four LBGs and seven LAEs are detected in NB3420. Using V-band data probing the rest-frame nonionizing UV, we observe that many NB3420-detected galaxies exhibit spatial offsets between their LyC and nonionizing UV emission and are characterized by extremely blue NB3420-V colors, corresponding to low ratios of nonionizing to ionizing radiation (F_UV_/F_LyC_) that are in tension with current stellar population synthesis models. We measure average values of (F_UV_/F_LyC_) for our LBG and LAE samples, correcting for foreground galaxy contamination and H I absorption in the intergalactic medium. We find (F_UV_/F_LyC_)_corr_^LBG^=82+/-45 and (F_UV_/F_LyC_)_corr_^LAE^=7.4+/-3.6. These flux density ratios correspond, respectively, to relative LyC escape fractions of f_esc,rel_^LBG^=5%-8%, and f_esc,rel_^LAE^=18%-49% absolute LyC escape fractions of f_esc,rel_^LBG^=1%-2% and f_esc,rel_^LAE^=5%-15%, and a comoving LyC emissivity from star-forming galaxies of 8.8-15.0x10^24^ erg/s/Hz/Mpc^3^. In order to study the differential properties of galaxies with and without LyC detections, we analyze narrowband Ly{alpha} imaging and rest-frame near-infrared imaging, finding that while LAEs with LyC detections have lower Ly{alpha} equivalent widths on average, there is no substantial difference in the rest-frame near-infrared colors of LBGs or LAEs with and without LyC detections. These preliminary results are consistent with an orientation-dependent model where LyC emission escapes through cleared paths in a patchy interstellar medium.
- ID:
- ivo://CDS.VizieR/J/AJ/119/2214
- Title:
- Photometry of Magellanic OB associations
- Short Name:
- J/AJ/119/2214
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine new CCD UBV photometry and spectroscopy with those from the literature to investigate 19 Magellanic Cloud OB associations that contain Wolf-Rayet (W-R) and other types of evolved, massive stars. Our spectroscopy reveals a wealth of newly identified interesting objects, including early O-type supergiants, a high-mass, double-lined binary in the SMC, and, in the LMC, a newly confirmed luminous blue variable (LBV; R85), a newly discovered W-R star (Sk -69^deg^ 194), and a newly found luminous B[e] star (LH 85-10). We use these data to provide precise reddening determinations and construct physical H-R diagrams for the associations.
- ID:
- ivo://CDS.VizieR/J/AJ/149/150
- Title:
- Photometry of multiples at NAOR and ASV in 2012
- Short Name:
- J/AJ/149/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 246 double or multiple stars were carried out during six nights in 2012. This is the seventh series of measurements of CCD frames of double and multiple stars obtained at Rozhen. Also in 2012, using the 0.6m telescope of the Serbian Astronomical Station on the mountain of Vidojevica, observations of 117 double or multiple stars were carried out during five nights. This is the second series of measurements of CCD frames of double and multiple stars obtained at this station. In this paper we present the results for the position angle and angular separation for 453 pairs and residuals for 105 pairs with published orbital elements or linear solutions. These observations have angular separations in the range from 1.50'' to 178.12'', with a median angular separation of 8.13''. We also present the recalculated linear solution for one pair and three linear solutions that have been calculated for the first time.
- ID:
- ivo://CDS.VizieR/J/ApJ/721/412
- Title:
- Photometry of polar CV* 1RXS J173006.4+033813
- Short Name:
- J/ApJ/721/412
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 1RXS J173006.4+033813, a polar cataclysmic variable with a period of 120.21 minutes. The white dwarf primary has a magnetic field of B=42^+6^_-5_MG and the secondary is an M3 dwarf. The system shows highly symmetric double-peaked photometric modulation in the active state as well as in quiescence. These arise from a combination of cyclotron beaming and ellipsoidal modulation. The projected orbital velocity of the secondary is K_2_=390+/-4km/s. We place an upper limit of 830+/-65pc on the distance.
- ID:
- ivo://CDS.VizieR/J/ApJ/728/14
- Title:
- Photometry of SN 2009bb
- Short Name:
- J/ApJ/728/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ultraviolet, optical, and near-infrared photometry and optical spectroscopy of the broad-lined Type Ic supernova (SN) 2009bb are presented, following the flux evolution from -10 to +285 days past B-band maximum. Thanks to the very early discovery, it is possible to place tight constraints on the SN explosion epoch. The expansion velocities measured from near maximum spectra are found to be only slightly smaller than those measured from spectra of the prototype broad-lined SN 1998bw associated with GRB 980425. Fitting an analytical model to the pseudobolometric light curve of SN 2009bb suggests that 4.1+/-1.9M_{sun}_ of material was ejected with 0.22+/-0.06M_{sun} of it being ^56^Ni. The resulting kinetic energy is 1.8+/-0.7x10^52^erg. This, together with an absolute peak magnitude of M_B_=-18.36+/-0.44, places SN 2009bb on the energetic and luminous end of the broad-lined Type Ic (SN Ic) sequence. Detection of helium in the early time optical spectra accompanied with strong radio emission and high metallicity of its environment makes SN 2009bb a peculiar object. Similar to the case for gamma-ray bursts (GRBs), we find that the bulk explosion parameters of SN 2009bb cannot account for the copious energy coupled to relativistic ejecta, and conclude that another energy reservoir (a central engine) is required to power the radio emission. Nevertheless, the analysis of the SN 2009bb nebular spectrum suggests that the failed GRB detection is not imputable to a large angle between the line-of-sight and the GRB beamed radiation. Therefore, if a GRB was produced during the SN 2009bb explosion, it was below the threshold of the current generation of {gamma}-ray instruments.
- ID:
- ivo://CDS.VizieR/J/A+A/592/A40
- Title:
- Photometry of SN 2013gh and iPTF13dge
- Short Name:
- J/A+A/592/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Temporal variability of narrow absorption lines in high-resolution spectra of Type Ia supernovae (SNe Ia) is studied to search for circumstellar matter. Time series which resolve the profiles of absorption lines such as NaI D or CaII H&K are expected to reveal variations due to photoionisation and subsequent recombination of the gases. The presence, composition, and geometry of circumstellar matter may hint at the elusive progenitor system of SNe Ia and could also affect the observed reddening law. To date, there are few known cases of time-varying NaI D absorption in SNe Ia, all of which occurred during relatively late phases of the supernova (SN) evolution. Photoionisation, however, is predicted to occur during the early phases of SNe Ia, when the supernovae peak in the ultraviolet. We attempt, therefore, to observe early-time absorption-line variations by obtaining high-resolution spectra of SNe before maximum light We have obtained photometry and high-resolution spectroscopy of SNe Ia 2013gh and iPTF 13dge, to search for absorption- line variations. Furthermore, we study interstellar absorption features in relation to the observed photometric colours of the SNe. Results. Both SNe display deep NaI D and CaII H&K absorption features. Furthermore, small but significant variations are detected in a feature of the NaI D profile of SN 2013gh. The variations are consistent with either geometric effects of rapidly moving or patchy gas clouds or photoionisation of NaI gas at R~=10^19^cm from the explosion. Our analysis indicates that it is necessary to focus on early phases to detect photoionisation effects of gases in the circumstellar medium of SNe Ia. Different absorbers such as NaI and CaII can be used to probe for matter at different distances from the SNe. The nondetection of variations during early phases makes it possible to put limits on the abundance of the species at those distances.
- ID:
- ivo://CDS.VizieR/J/AJ/123/2822
- Title:
- Photometry of southern NLTT stars
- Short Name:
- J/AJ/123/2822
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRI photometry of 180 bright, southern nearby-star candidates. The stars were selected from the New Luyten Two-Tenths proper-motion catalog (Cat. <I/98>) based on optical/infrared colors, constructed by combining Luyten's m_r_ estimates with near-infrared photometry from the Two Micron All Sky Survey (Cat. <B/2mass>) . Photometric parallaxes derived from V-Ks, V-I, and I-J colors, combined with the limited available astrometry, show that as many as 108 stars may lie within 20pc of the Sun. Of these, 53 are new to nearby-star catalogs, including three within 10pc of the Sun.
