- ID:
- ivo://CDS.VizieR/J/MNRAS/433/1871
- Title:
- UBVRI griz light curves of SN 2012aw
- Short Name:
- J/MNRAS/433/1871
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present densely sampled UBVRI/griz photometric and low-resolution (6-10{AA}) optical spectroscopic observations from 4 to 270d after explosion of a newly discovered Type II SN 2012aw in a nearby (~9.9Mpc) galaxy M95. The light-curve characteristics of apparent magnitudes, colours, bolometric luminosity and the presence and evolution of prominent spectral features are found to have striking similarity with the archetypal IIP SNe 1999em, 1999gi and 2004et. The early time observations of SN 2012aw clearly detect minima in the light curve of V, R and I bands near 37d after explosion and this we suggest to be an observational evidence for emergence of recombination phase. The mid-plateau M_V_ magnitude (-16.67+/-0.04) lies in between the bright (~-18) and subluminous (~-15) IIP SNe. The mass of nickel is 0.06+/-0.01M{sun}. The synow modelling of spectra indicate that the value and evolution of the photospheric velocity is similar to SN 2004et, but about ~600km/s higher than that of SNe 1999em and 1999gi at comparable epochs. This trend is more apparent in the line velocities of H{alpha} and H{beta}. A comparison of ejecta velocity properties with that of existing radiation-hydrodynamical simulations indicate that the energy of explosion lies in the range 1-2x10^51^ergs; a further comparison of nebular phase [OI] doublet luminosity with SNe 2004et and 1987A indicate that the mass of progenitor star is about 14 to 15M_{sun}_. The presence of high-velocity absorption features in the mid-to-late plateau and possibly in early phase spectra show signs of interaction between ejecta and the circumstellar matter; being consistent with its early time detection at X-ray and radio wavebands.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/NewA/15.108
- Title:
- UBVRIH{alpha} of {eta} Car in 2009
- Short Name:
- J/other/NewA/15.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The periodic events occurring in {eta} Carinae have been widely monitored during the last three 5.5-year cycles. The last one recently occurred in January 2009 and more exhaustive observations have been made at different wavelength ranges. If these events are produced when the binary components approach periastron, the timing and sampling of the photometric features can provide more information about the geometry and physics of the system. Thus, we continued with our ground-based optical photometric campaign started in 2003 to record the behaviour of the 2009.0 event in detail. This time the observation program included a new telescope to obtain information from other photometric bands. The daily monitoring consists of the acquisition of CCD images through standard UBVRI filters and a narrow H{alpha} passband. The subsequent differential photometry includes the central region of the object and the whole Homunculus nebula. The results of our relative UBVRIH{alpha} photometry, performed from November 2008 up to the end of March 2009, are presented in this work, which comprises the totality of the event. The initial rising branch, the maximum, the dip to the minimum and the recovering rising phase strongly resemble a kind of eclipse. All these features happened on time - according to that predicted - although there are some photometric differences in comparison with the previous event. We made a new determination of 2022.8 days for the period value using the present and previous "eclipse-like" event data. These results strongly support the binarity hypothesis for {eta} Car. In this paper, the complete dataset with the photometry of the 2009.0 event is provided to make it readily available for further analysis.
- ID:
- ivo://CDS.VizieR/J/A+A/511/A25
- Title:
- UBVRIH{alpha} photometry of NGC6383
- Short Name:
- J/A+A/511/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The very young open cluster NGC 6383 centered on the O-star binary HD 159176 is an interesting place for studying the impact of early-type stars with strong radiation fields and powerful winds on the formation processes of low-mass stars. To investigate this process, it is necessary to determine the characteristics (age, presence, or absence of circumstellar material) of the population of low-mass pre-main-sequence (PMS) stars in the cluster. We obtained deep U B V Rc Ic H{alpha} photometric data of the entire cluster as well as medium-resolution optical spectroscopy of a subsample of X-ray selected objects. Our spectroscopic data reveal only very weak H{alpha} emission lines in a few X-ray selected PMS candidates. We photometrically identify a number of H-{alpha} emission candidates but their cluster membership is uncertain. We find that the fainter objects in the field of view have a wide range of extinction (up to A_V_=20), one X-ray selected OB star having A_V_~8. Our investigation uncovers a population of PMS stars in NGC 6383 that are probably coeval with HD 159176. In addition, we detect a population of reddened objects that are probably located at different depths within the natal molecular cloud of the cluster. Finally, we identify a rather complex spatial distribution of H{alpha} emitters, which is probably indicative of a severe contamination by foreground and background stars.
- ID:
- ivo://CDS.VizieR/J/A+A/402/549
- Title:
- UBVRIHalpha photometry of NGC 3293
- Short Name:
- J/A+A/402/549
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep and extensive CCD photometric observations at UBV(RI)cH{alpha} were carried out in the area of the open cluster NGC 3293. The new data set allows to see the entire cluster sequence down to Mv~+4.5, revealing that stars with Mv<-2 are evolving off the main sequence; stars with -2<Mv<+2 are located on the main sequence and stars with Mv>+2 are placed above it. According to our analysis, the cluster distance is d=2750+/-250pc (V0-Mv=12.2+/-0.2) and its nuclear age is 8+/-1Myr. NGC 3293 contains an important fraction of pre-main sequence (PMS) stars distributed along a parallel band to the ZAMS with masses from 1 to 2.5M_{sun}_ and a mean contraction age of 10Myr. This last value does not differ too much from the nuclear age estimate. If we take into account the many factors that may affect the PMS star positions on the colour-magnitude diagram, both ages can be perfectly reconciled. The star formation rate, on the other hand, suggests that NGC 3293 stars formed surely in one single event, therefore favouring a coeval process of star formation. Using the Halpha data, we detected nineteen stars with signs of Halpha emission in the region of NGC 3293, another indication that the star formation process is still active in the region. The computed initial mass function for the cluster has a slope of x=1.2+/-0.2, a bit flatter than the typical slope for field stars and similar to the values found for other young open clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/114/2644
- Title:
- UBVRIHa photometry of NGC2264
- Short Name:
- J/AJ/114/2644
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVRI H{alpha} CCD photometry has been obtained fro the young cluster NGC 2264. Using (R-H{alpha}) color, a measure of H{alpha} emission, we selected member stars in the pre-main sequence (PMS) stage.
- ID:
- ivo://CDS.VizieR/J/PASP/124/140
- Title:
- UBVRI Hp BT and VT photonic responses
- Short Name:
- J/PASP/124/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have calculated improved photonic passbands for the UBVRI, Hipparcos Hp, and Tycho BT and VT standard systems using the extensive spectrophotometric libraries of NGSL and MILES. Using the Hp passband, we adjusted the absolute flux levels of stars in the spectrophotometric libraries so that their synthetic Hp magnitudes matched the precise Hipparcos Catalogue value. Synthetic photometry based on the renormalized fluxes was compared with the standard UBVRI, BT and VT magnitudes, and revised synthetic zero points were determined. The Hipparcos and Tycho photometry system zero points were also compared with the V-magnitude zero points of the SAAO UBVRI system, the homogenized UBV system, and the Walraven VB system.
- ID:
- ivo://CDS.VizieR/J/A+A/605/A99
- Title:
- UBVRI images of Barnard 207
- Short Name:
- J/A+A/605/A99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Barnard 207 (B207, LDN 1489, LBN 777), also known as the Vulture Head nebula, is a cometary globule in the Taurus-Auriga-Perseus Molecular Cloud region. B207 is known to host a Class I protostar, IRAS 04016+2610, located at a projected distance of ~8400au from the dense core centre. Using imaging and photometry over a wide wavelength range, from UV to sub-mm, we study the physical properties of B207 and the dust grains contained within. The core density, temperature, and mass are typical of other globules found in the Milky Way interstellar medium (ISM). The increase in the dust albedo with increasing optical wavelengths, along with the detection of coreshine in the near infrared, indicates the presence of larger dust grains in B207. The measured optical, near-, mid- and far-infrared intensities are in agreement with the CMM+AMM and CMM+AMMI dust grain type of the THEMIS model, suggesting mantle formation on the dust grains throughout the globule. We investigate the possibility of turbulence being responsible for diffusing dust grains from the central core to external outer layers of B207. However, in situ formation of large dust grains cannot be excluded.
- ID:
- ivo://CDS.VizieR/J/ApJS/193/1
- Title:
- UBVRIJHK color-temperature calibration
- Short Name:
- J/ApJS/193/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A collection of Johnson/Cousins photometry for stars with known [Fe/H] is used to generate color-color relations that include the abundance dependence. Literature temperature and bolometric correction (BC) dependences are attached to the color relations. The JHK colors are transformed to the Bessell & Brett (1988PASP..100.1134B) homogenized system. The main result of this work is the tabulation of seven colors and the V-band BC as a function of Teff, logg, and [Fe/H] for -1.06<V-K<10.2 and an accompanying interpolation program. Improvements to the present calibration would involve filling photometry gaps, obtaining more accurate and on-system photometry, knowing better logg and [Fe/H] values, improving the statistics for data-impoverished groups of stars such as metal-poor K dwarfs, applying small tweaks in the processing pipeline, and obtaining better empirical temperature and BC relations, especially for supergiants and M stars. A way to estimate dust extinction from M dwarf colors is pointed out.
- ID:
- ivo://CDS.VizieR/J/ApJS/101/117
- Title:
- UBVRIJHKLMNQ photometry in Taurus-Auriga
- Short Name:
- J/ApJS/101/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper analyzes optical and infrared photometry of pre-main- sequence stars in the Taurus-Auriga molecular cloud. More than half of the stars in our sample have excess near-infrared emission. The near-infrared excesses correlate very well with other measures of activity, such as Halpha emission, ultraviolet excess emission, millimeter continuum emission, and the presence of reflection nebulae and molecular outflows. The infrared colors and the ratio of far-infrared to bolometric luminosity display a smooth progression from the most deeply embedded protostars to optically visible T Tauri stars. Infalling envelope models account for the colors of protostars; simple disk models similarly reproduce the colors of many T Tauri stars. Both the stellar birth line and a 10^5yr isochrone provide a reasonable upper envelope to the luminosity distribution of optically visible stars in the H-R diagram. Only a few stars in the cloud have apparent ages exceeding 2-3x10^6yr, as derived from detailed stellar evolution calculations. The distribution of stars in the H-R diagram indicates that the cloud has formed stars at a roughly constant rate for the past 1-2x10^6yr. Analyses of the J- and K-luminosity functions support this conclusion. Within the uncertainties, the observed mass distribution for optically visible stars agrees with a Miller-Scalo initial mass function. Source statistics imply a lifetime of 1-2x10^5yr for the typical protostar in Taurus-Auriga. There is no evidence, however, that these sources lie on the stellar birth line. Indeed, the protostellar luminosity function is essentially identical to the luminosity function derived for optically visible T Tauri stars in the cloud. These results provide some support for the evolutionary sequence -- embedded protostar -> T Tauri star with a circumstellar disk -> T Tauri star without a circumstellar disk -- currently envisioned in standard models of low-mass star formation. Source statistics and infrared color-color diagrams demonstrate that pre-main-sequence stars develop bluer colors and display less evidence for circumstellar material with time. The data show little evidence, however, for the luminosity evolution expected along the proposed evolutionary sequence. Time-dependent accretion during the infall phase may account for the low luminosity of Taurus-Auriga protostars; this hypothesis requires more tests.
- ID:
- ivo://CDS.VizieR/J/A+AS/93/383
- Title:
- UBVRIJHKL photometry of symbiotic stars
- Short Name:
- J/A+AS/93/383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
