scholarly journals AT 2019abn: multi-wavelength observations over the first 200 days

2020 ◽  
Vol 637 ◽  
pp. A20 ◽  
Author(s):  
S. C. Williams ◽  
D. Jones ◽  
P. Pessev ◽  
S. Geier ◽  
R. L. M. Corradi ◽  
...  
Keyword(s):  
Light Curve ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Absolute Magnitude ◽  
Low Velocity ◽  
Optical Telescope ◽  
Circumstellar Material ◽  
Medium Resolution ◽  
Multi Wavelength ◽  
Optical Light Curve

Context. AT 2019abn was discovered in the nearby M51 galaxy by the Zwicky Transient Facility at more than two magnitudes and around three weeks prior to its optical peak. Aims. We aim to conduct a detailed photometric and spectroscopic follow-up campaign for AT 2019abn, with early discovery allowing for significant pre-maximum observations of an intermediate luminosity red transient (ILRT) for the first time. Methods. This work is based on the analysis of u′BVr′i′z′H photometry and low-resolution spectroscopy using the Liverpool Telescope, medium-resolution spectroscopy with the Gran Telescopio Canarias (GTC), and near-infrared imaging with the GTC and the Nordic Optical Telescope. Results. We present the most detailed optical light curve of an ILRT to date, with multi-band photometry starting around three weeks before peak brightness. The transient peaked at an observed absolute magnitude of Mr′ = −13.1, although it is subject to significant reddening from dust in M51, implying an intrinsic Mr′ ∼ −15.2. The initial light curve showed a linear, achromatic rise in magnitude before becoming bluer at peak. After peak brightness, the transient gradually cooled. This is reflected in our spectra, which at later times show absorption from such species as Fe I, Ni I and Li I. A spectrum taken around peak brightness shows narrow, low-velocity absorption lines, which we interpret as likely to originate from pre-existing circumstellar material. Conclusions. We conclude that while there are some peculiarities, such as the radius evolution, AT 2019abn fits in well overall with the ILRT class of objects and is the most luminous member of the class seen to date.

Early Blue Excess from the Type Ia Supernova 2017cbv

2017 ◽  
Vol 14 (S339) ◽  
pp. 47-49
Author(s):  
G. Hosseinzadeh
Keyword(s):  
Light Curve ◽  
Standard Type ◽  
Circumstellar Material ◽  
Type Ia Supernova ◽  
Unusual Distribution ◽  
Photometric Observations ◽  
Type Ia ◽  
Optical Light Curve ◽  
Ia Supernovae

AbstractThis paper presented very early, high-cadence photometric observations of the nearby Type Ia SN 2017cbv. The light-curve is unique in that during the first five days of observations it has a blue bump in the U, B, and g bands which is clearly resolved by virtue of our photometric cadence of 5.7 hr during that time span. We modelled the light-curve as the combination of an early shock of the supernova ejecta against a non-degenerate companion star plus a standard Type Ia supernova component. Our best-fit model suggested the presence of a subgiant star 56 R⊙ from the exploding white dwarf, although that number is highly model-dependent. While the model matches the optical light-curve well, it over-predicts the flux expected in the ultraviolet bands. That may indicate that the shock is not a blackbody, perhaps because of line blanketing in the UV. Alternatively, it could point to another physical explanation for the optical blue bump, such as interaction with circumstellar material or an unusual distribution of the element Ni. Early optical spectra of SN 2017cbv show strong carbon absorption as far as day –13 with respect to maximum light, suggesting that the progenitor system contained a significant amount of unburnt material. These results for SN 2017cbv illustrate the power of early discovery and intense follow-up of nearby supernovæ for resolving standing questions about the progenitor systems and explosion mechanisms of Type Ia supernovæ.

scholarly journals The deep Chandra survey in the SDSS J1030+0524 field

2020 ◽  
Vol 637 ◽  
pp. A52 ◽  
Author(s):  
R. Nanni ◽  
R. Gilli ◽  
C. Vignali ◽  
M. Mignoli ◽  
A. Peca ◽  
...  
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Cumulative Number ◽  
Imaging Data ◽  
X Ray ◽  
Large Scale Structures ◽  
Multi Wavelength ◽  
Deep Fields ◽  
Initial Source

We present the X-ray source catalog for the ∼479 ks Chandra exposure of the SDSS J1030+0524 field, which is centered on a region that shows the best evidence to date of an overdensity around a z > 6 quasar, and also includes a galaxy overdensity around a Compton-thick Fanaroff-Riley type II (FRII) radio galaxy at z = 1.7. Using wavdetect for initial source detection and ACIS Extract for source photometry and significance assessment, we create preliminary catalogs of sources that are detected in the full (0.5−7.0 keV), soft (0.5−2.0 keV), and hard (2−7 keV) bands, respectively. We produce X-ray simulations that mirror our Chandra observation to filter our preliminary catalogs and achieve a completeness level of > 91% and a reliability level of ∼95% in each band. The catalogs in the three bands are then matched into a final main catalog of 256 unique sources. Among them, 244, 193, and 208 are detected in the full, soft, and hard bands, respectively. The Chandra observation covers a total area of 335 arcmin2 and reaches flux limits over the central few square arcmins of ∼3 × 10−16, 6 × 10−17, and 2 × 10−16 erg cm−2 s−1 in the full, soft, and hard bands, respectively This makes J1030 field the fifth deepest extragalactic X-ray survey to date. The field is part of the Multiwavelength Survey by Yale-Chile (MUSYC), and is also covered by optical imaging data from the Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT), near-infrared imaging data from the Canada France Hawaii Telescope WIRCam (CFHT/WIRCam), and Spitzer IRAC. Thanks to its dense multi-wavelength coverage, J1030 represents a legacy field for the study of large-scale structures around distant accreting supermassive black holes. Using a likelihood ratio analysis, we associate multi-band (r, z, J, and 4.5 μm) counterparts for 252 (98.4%) of the 256 Chandra sources, with an estimated reliability of 95%. Finally, we compute the cumulative number of sources in each X-ray band, finding that they are in general agreement with the results from the Chandra Deep Fields.

scholarly journals SN 2016gsd: an unusually luminous and linear Type II supernova with high velocities

2020 ◽  
Vol 493 (2) ◽  
pp. 1761-1781 ◽  
Author(s):  
T M Reynolds ◽  
M Fraser ◽  
S Mattila ◽  
M Ergon ◽  
L Dessart ◽  
...  
Keyword(s):  
Light Curve ◽  
Massive Star ◽  
Absolute Magnitude ◽  
Host Galaxy ◽  
Type Ii ◽  
High Luminosity ◽  
Linear Type ◽  
Circumstellar Material ◽  
Low Metallicity ◽  
Edge Tracing

ABSTRACT We present observations of the unusually luminous Type II supernova (SN) 2016gsd. With a peak absolute magnitude of V = −19.95 ± 0.08, this object is one of the brightest Type II SNe, and lies in the gap of magnitudes between the majority of Type II SNe and the superluminous SNe. Its light curve shows little evidence of the expected drop from the optically thick phase to the radioactively powered tail. The velocities derived from the absorption in H α are also unusually high with the blue edge tracing the fastest moving gas initially at 20 000 km s−1, and then declining approximately linearly to 15 000 km s−1 over ∼100 d. The dwarf host galaxy of the SN indicates a low-metallicity progenitor which may also contribute to the weakness of the metal lines in its spectra. We examine SN 2016gsd with reference to similarly luminous, linear Type II SNe such as SNe 1979C and 1998S, and discuss the interpretation of its observational characteristics. We compare the observations with a model produced by the jekyll code and find that a massive star with a depleted and inflated hydrogen envelope struggles to reproduce the high luminosity and extreme linearity of SN 2016gsd. Instead, we suggest that the influence of interaction between the SN ejecta and circumstellar material can explain the majority of the observed properties of the SN. The high velocities and strong H α absorption present throughout the evolution of the SN may imply a circumstellar medium configured in an asymmetric geometry.

scholarly journals A multi-wavelength classification system for the evolution of star clusters

2015 ◽  
Vol 11 (S315) ◽  
pp. 142-145
Author(s):  
Bradley C. Whitmore ◽  
Crystal Brogan ◽  
Rupali Chandar ◽  
Aaron Evans ◽  
John Hibbard ◽  
...  
Keyword(s):  
Classification System ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Cluster Formation ◽  
Star Clusters ◽  
Radio Continuum ◽  
Optical Observations ◽  
Small Scale ◽  
Molecular Gas ◽  
Multi Wavelength

AbstractThe availability of high spatial resolution molecular gas observations from ALMA, and similar resolution observations in the radio continuum using the VLA, is providing the opportunity to make comparisons with specific features seen in optical observations more directly than in the past. Using our ALMA observations of the Antennae galaxies as a springboard, we have compared the locations of small-scale CO (3−2) features with a variety of multi-wavelength observations, in particular optical and near-infrared imaging using both broad (UBVI) and narrow-band data (Hαand Paβ) taken with the HST, and radio (3.6 cm) continuum observations taken with the VLA. This comparison leads to the development of an evolutionary classification system which provides a framework for studying the sequence of star cluster formation and evolution, from diffuse Giant Molecular Clouds (GMCs), to proto, embedded, emerging, young, and intermediate/old star clusters. Using this evolutionary framework, we estimate the maximum age range of clusters formed in a single GMC is approximately 10 Myr. This suggests that the molecular gas is removed over this timescale, resulting in the cessation of star formation and the destruction of the GMC within a radius of about 200 pc.

scholarly journals Type IIn supernova light-curve properties measured from an untargeted survey sample

2020 ◽  
Vol 637 ◽  
pp. A73 ◽  
Author(s):  
A. Nyholm ◽  
J. Sollerman ◽  
L. Tartaglia ◽  
F. Taddia ◽  
C. Fremling ◽  
...  
Keyword(s):  
Light Curve ◽  
Template Matching ◽  
Statistical Significance ◽  
Absolute Magnitude ◽  
Late Time ◽  
Host Galaxies ◽  
Magnitude Distribution ◽  
Optical Light Curve ◽  
History Of ◽  
Survey Sample

The evolution of a Type IIn supernova (SN IIn) is governed by the interaction between the SN ejecta and a hydrogen-rich circumstellar medium. The SNe IIn thus allow us to probe the late-time mass-loss history of their progenitor stars. We present a sample of SNe IIn from the untargeted, magnitude-limited surveys of the Palomar Transient Factory (PTF) and its successor, the intermediate PTF (iPTF). To date, statistics on SN IIn optical light-curve properties have generally been based on small (≲10 SNe) samples from targeted SN surveys. The SNe IIn found and followed by the PTF/iPTF were used to select a sample of 42 events with useful constraints on the rise times as well as with available post-peak photometry. The sample SNe were discovered in 2009−2016 and have at least one low-resolution classification spectrum, as well as photometry from the P48 and P60 telescopes at Palomar Observatory. We study the light-curve properties of these SNe IIn using spline fits (for the peak and the declining portion) and template matching (for the rising portion). We study the peak-magnitude distribution, rise times, decline rates, colour evolution, host galaxies, and K-corrections of the SNe in our sample. We find that the typical rise times are divided into fast and slow risers at 20 ± 6 d and 50 ± 11 d, respectively. The decline rates are possibly divided into two clusters (with slopes 0.013 ± 0.006 mag d−1 and 0.040 ± 0.010 mag d−1), but this division has weak statistical significance. We find no significant correlation between the peak luminosity of SNe IIn and their rise times, but the more luminous SNe IIn are generally found to be more long-lasting. Slowly rising SNe IIn are generally found to decline slowly. The SNe in our sample were hosted by galaxies of absolute magnitude −22 ≲ Mg ≲ −13 mag. The K-corrections at light-curve peak of the SNe IIn in our sample are found to be within 0.2 mag for the observer’s frame r-band, for SNe at redshifts z <  0.25. By applying K-corrections and also including ostensibly “superluminous” SNe IIn, we find that the peak magnitudes are Mrpeak = −19.18 ± 1.32 mag. We conclude that the occurrence of conspicuous light-curve bumps in SNe IIn, such as in iPTF13z, are limited to 1.4+14.6−1.0 % of the SNe IIn. We also investigate a possible sub-type of SNe IIn with a fast rise to a ≳50 d plateau followed by a slow, linear decline.

scholarly journals Quest for the Upcoming Periastron Passage of an Episodic Dust Maker and Particle-accelerating Colliding-wind Binary: WR 125

2021 ◽  
Vol 162 (6) ◽  
pp. 257
Author(s):  
Bharti Arora ◽  
J. C. Pandey ◽  
Michaël De Becker ◽  
S. B. Pandey ◽  
Nand K. Chakradhari ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Recurrence Time ◽  
Time Interval ◽  
Wide Field ◽  
X Rays ◽  
Optical Telescope ◽  
X Ray ◽  
Enhanced Absorption

Abstract We have carried out a long-term infrared and X-ray investigation of the colliding-wind binary WR 125 (WC7 + O9III). The source was monitored using AstroSat Soft X-ray Telescope and the Tata Institute of Fundamental Research Near Infrared Imaging Camera-II mounted at the back of 3.6 m Devasthal Optical Telescope. WR 125 appeared brighter in the near-infrared K-band during the years 2017–2021 which is attributed to another episode of dust formation similar to the one reported during the likely periastron passage at the beginning of the 1990s. This is further supported by enhanced emission observed in the W1 and W2 bands of Wide-field Infrared Survey Explorer from 2018–2019. By combining archival X-ray data sets with our new measurements, long-term variations have been noticed. The source reaches a lower emission state in 2020 June (close to the recent infrared maximum) which could be due to enhanced absorption of X-rays produced in the colliding-wind region by the WC stellar wind close to the periastron in an eccentric orbit. The time interval between the previous and latest X-ray low states may indicate an orbital period of 28–29 years, in fair agreement with the recurrence time of episodic dust production. We also discuss published radio measurements in the context of a common picture based on a long-period binary scenario. These results allow us to draw relevant guidelines for future multiwavelength observations of WR 125.

scholarly journals The slow demise of the long-lived SN 2005ip

2020 ◽  
Vol 498 (1) ◽  
pp. 517-531
Author(s):  
Ori D Fox ◽  
Claes Fransson ◽  
Nathan Smith ◽  
Jennifer Andrews ◽  
K Azalee Bostroem ◽  
...  
Keyword(s):  
Light Curve ◽  
Mass Loss ◽  
Near Infrared ◽  
Mass Loss Rate ◽  
Uv Spectra ◽  
Shock Interaction ◽  
Radiated Energy ◽  
Show Evidence ◽  
Optical Light Curve ◽  
The Rich

ABSTRACT The Type IIn supernova (SN IIn) 2005ip is one of the most well-studied and long-lasting examples of an SN interacting with its circumstellar environment. The optical light curve plateaued at a nearly constant level for more than five years, suggesting ongoing shock interaction with an extended and clumpy circumstellar medium (CSM). Here, we present continued observations of the SN from ∼1000 to 5000 d post-explosion at all wavelengths, including X-ray, ultraviolet, near-infrared (NIR), and mid-infrared. The UV spectra probe the pre-explosion mass loss and show evidence for CNO processing. From the bolometric light curve, we find that the total radiated energy is in excess of 1050 erg, the progenitor star’s pre-explosion mass-loss rate was ${\gtrsim}1 \times 10^{-2}\, {\rm M_{\odot }~ yr}^{-1}$, and the total mass lost shortly before explosion was ${\gtrsim}1\, {\rm M_\odot }$, though the mass lost could have been considerably larger depending on the efficiency for the conversion of kinetic energy to radiation. The ultraviolet through NIR spectrum is characterized by two high-density components, one with narrow high-ionization lines, and one with broader low-ionization H i, He i, [O i], Mg ii, and Fe ii lines. The rich Fe ii spectrum is strongly affected by Lyα fluorescence, consistent with spectral modelling. Both the Balmer and He i lines indicate a decreasing CSM density during the late interaction period. We find similarities to SN 1988Z, which shows a comparable change in spectrum at around the same time during its very slow decline. These results suggest that, at long last, the shock interaction in SN 2005ip may finally be on the decline.

scholarly journals Discovery of bright z ~ 7 galaxies in the UltraVISTA survey

2012 ◽  
Vol 8 (S295) ◽  
pp. 22-22
Author(s):  
Rebecca A. A. Bowler ◽  
James S. Dunlop ◽  
Ross J. McLure
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Small Sample ◽  
Optical Data ◽  
Dwarf Stars ◽  
Photometric Redshift ◽  
Redshift Galaxy ◽  
The Galaxy ◽  
Multi Wavelength ◽  
Galaxy Luminosity Function

AbstractWe have exploited the new, deep, near-infrared Y,J,H,Ks UltraVISTA imaging of the COSMOS field, in tandem with deep optical and mid-infrared imaging, to conduct a new search for luminous galaxies at redshifts z ≃ 7. We have utilised this unique multi-wavelength dataset to select galaxy candidates at redshifts z > 6.5 by searching first for Y+J-detected objects which are undetected in the CFHT and HST optical data. This sample was then refined using a photometric redshift fitting code, enabling the rejection of lower-redshift galaxy contaminants and cool galactic M, L, T dwarf stars. The final result of this process is a small sample of (at most) ten credible galaxy candidates at z > 6.5 (from over 200,000 galaxies detected in the year-one UltraVISTA data). The new z ≃ 7 galaxies reported here are the first credible z ≃ 7 Lyman-break galaxies discovered in the COSMOS field and, as the most UV-luminous discovered to date at these redshifts, are prime targets for deep follow-up spectroscopy. We explore their physical properties, and briefly consider the implications of their inferred number density for the form of the galaxy luminosity function at z ≃ 7.

scholarly journals SN 2019muj – a well-observed Type Iax supernova that bridges the luminosity gap of the class

2020 ◽  
Vol 501 (1) ◽  
pp. 1078-1099
Author(s):  
Barnabás Barna ◽  
Tamás Szalai ◽  
Saurabh W Jha ◽  
Yssavo Camacho-Neves ◽  
Lindsey Kwok ◽  
...  
Keyword(s):  
Light Curve ◽  
Spectroscopic Data ◽  
Near Infrared ◽  
Early Time ◽  
Absolute Magnitude ◽  
Good Match ◽  
Chemical Abundance ◽  
Synthetic Spectra ◽  
Short Rise Time

ABSTRACT We present early-time (t &lt; +50 d) observations of SN 2019muj (=ASASSN-19tr), one of the best-observed members of the peculiar SN Iax class. Ultraviolet and optical photometric and optical and near-infrared spectroscopic follow-up started from ∼5 d before maximum light [tmax(B) on $58707.8$ MJD] and covers the photospheric phase. The early observations allow us to estimate the physical properties of the ejecta and characterize the possible divergence from a uniform chemical abundance structure. The estimated bolometric light-curve peaks at 1.05 × 1042 erg s−1 and indicates that only 0.031 M⊙ of 56Ni was produced, making SN 2019muj a moderate luminosity object in the Iax class with peak absolute magnitude of $M_\rm {V} = -16.4$ mag. The estimated date of explosion is t0 = $58698.2$ MJD and implies a short rise time of trise = 9.6 d in B band. We fit of the spectroscopic data by synthetic spectra, calculated via the radiative transfer code tardis. Adopting the partially stratified abundance template based on brighter SNe Iax provides a good match with SN 2019muj. However, without earlier spectra, the need for stratification cannot be stated in most of the elements, except carbon, which is allowed to appear in the outer layers only. SN 2019muj provides a unique opportunity to link extremely low-luminosity SNe Iax to well-studied, brighter SNe Iax.

scholarly journals TIFR Near Infrared Imaging Camera-II on the 3.6 m Devasthal Optical Telescope

2018 ◽  
Vol 07 (01) ◽  
pp. 1850003 ◽  
Author(s):  
T. Baug ◽  
D. K. Ojha ◽  
S. K. Ghosh ◽  
S. Sharma ◽  
A. K. Pandey ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Wide Field ◽  
Near Infrared Imaging ◽  
Optical Telescope ◽  
Estimated Parameters ◽  
Imaging Camera ◽  
Polycyclic Aromatic ◽  
Fundamental Research ◽  
Pixel Scale

Tata Institute of Fundamental Research (TIFR) Near Infrared Imaging Camera-II (TIRCAM2) is a closed-cycle Helium cryo-cooled imaging camera equipped with a Raytheon 512[Formula: see text][Formula: see text][Formula: see text]512 pixels InSb Aladdin III Quadrant focal plane array (FPA) having sensitivity to photons in the 1–5[Formula: see text][Formula: see text] wavelength band. In this paper, we present the performance of the camera on the newly installed 3.6[Formula: see text]m Devasthal Optical Telescope (DOT) based on the calibration observations carried out during 2017 May 11–14 and 2017 October 7–31. After the preliminary characterization, the camera has been released to the Indian and Belgian astronomical community for science observations since 2017 May. The camera offers a field-of-view (FoV) of [Formula: see text] on the DOT with a pixel scale of 0.169[Formula: see text]. The seeing at the telescope site in the near-infrared (NIR) bands is typically sub-arcsecond with the best seeing of [Formula: see text] realized in the NIR [Formula: see text]-band on 2017 October 16. The camera is found to be capable of deep observations in the [Formula: see text], [Formula: see text] and [Formula: see text] bands comparable to other 4[Formula: see text]m class telescopes available world-wide. Another highlight of this camera is the observational capability for sources up to Wide-field Infrared Survey Explorer (WISE) W1-band (3.4[Formula: see text][Formula: see text]m) magnitudes of 9.2 in the narrow [Formula: see text]-band ([Formula: see text]; [Formula: see text] 3.59[Formula: see text][Formula: see text]m). Hence, the camera could be a good complementary instrument to observe the bright [Formula: see text]-band sources that are saturated in the Spitzer-Infrared Array Camera (IRAC) ([3.6] [Formula: see text] 7.92 mag) and the WISE W1-band ([3.4] [Formula: see text] 8.1 mag). Sources with strong polycyclic aromatic hydrocarbon (PAH) emission at 3.3[Formula: see text][Formula: see text]m are also detected. Details of the observations and estimated parameters are presented in this paper.

Sign in / Sign up

Export Citation Format

Share Document