96 research outputs found
The Carnegie Supernova Project I: photometry data release of low-redshift stripped-envelope supernovae
The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated
supernova follow-up program based at the Las Campanas Observatory that
collected science data of young, low-redshift supernovae between 2004 and 2009.
Presented in this paper is the CSP-I photometric data release of low-redshift
stripped-envelope core-collapse supernovae. The data consist of optical
(uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared
(YJH) photometry. Twenty objects have optical pre-maximum coverage with a
subset of 12 beginning at least five days prior to the epoch of B-band maximum
brightness. In the near-infrared, 17 objects have pre-maximum observations with
a subset of 14 beginning at least five days prior to the epoch of J-band
maximum brightness. Analysis of this photometric data release is presented in
companion papers focusing on techniques to estimate host-galaxy extinction
(Stritzinger et al., submitted) and the light-curve and progenitor star
properties of the sample (Taddia et al., submitted). The analysis of an
accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the
subject of a future paper.Comment: Updated a couple of small error
Recommended from our members
Feasibility of Space Charge Measurements on HVDC Cable Joints
This review article aims at illustrating the starting of the activities carried out by the Study Group from the viewpoint of the assessment of the state of the art in the measurement of SC in HVDC extruded cable system joints
Transition from Fireball to Poynting-flux-dominated Outflow in Three-Episode GRB 160625B
The ejecta composition is an open question in gamma-ray bursts (GRB) physics.
Some GRBs possess a quasi-thermal spectral component in the time-resolved
spectral analysis, suggesting a hot fireball origin. Others show a featureless
non-thermal spectrum known as the "Band" function, consistent with a
synchrotron radiation origin and suggesting that the jet is
Poynting-flux-dominated at the central engine and likely in the emission region
as well. There are also bursts showing a sub-dominant thermal component and a
dominant synchrotron component suggesting a likely hybrid jet composition. Here
we report an extraordinarily bright GRB 160625B, simultaneously observed in
gamma-rays and optical wavelengths, whose prompt emission consists of three
isolated episodes separated by long quiescent intervals, with the durations of
each "sub-burst" being 0.8 s, 35 s, and 212 s, respectively. Its high
brightness (with isotropic peak luminosity L
erg/s) allows us to conduct detailed time-resolved spectral analysis in each
episode, from precursor to main burst and to extended emission. The spectral
properties of the first two sub-bursts are distinctly different, allowing us to
observe the transition from thermal to non-thermal radiation between
well-separated emission episodes within a single GRB. Such a transition is a
clear indication of the change of jet composition from a fireball to a
Poynting-flux-dominated jet.Comment: Revised version reflecting the referees' comments. 27 pages, 11
figures, 5 tables. The final edited version will appear in Nature Astronom
Carnegie Supernova Project II: The slowest rising Type Ia supernova LSQ14fmg and clues to the origin of super-Chandrasekhar/03fg-like events
The Type Ia supernova (SN Ia) LSQ14fmg exhibits exaggerated properties which
may help to reveal the origin of the "super-Chandrasekhar" (or 03fg-like)
group. The optical spectrum is typical of a 03fg-like SN Ia, but the light
curves are unlike those of any SNe Ia observed. The light curves of LSQ14fmg
rise extremely slowly. At -23 rest-frame days relative to B-band maximum,
LSQ14fmg is already brighter than =-19 mag before host extinction
correction. The observed color curves show a flat evolution from the earliest
observation to approximately one week after maximum. The near-infrared light
curves peak brighter than -20.5 mag in the J and H bands, far more luminous
than any 03fg-like SNe Ia with near-infrared observations. At one month past
maximum, the optical light curves decline rapidly. The early, slow rise and
flat color evolution are interpreted to result from an additional excess flux
from a power source other than the radioactive decay of the synthesized
. The excess flux matches the interaction with a typical superwind of
an asymptotic giant branch (AGB) star in density structure, mass-loss rate, and
duration. The rapid decline starting at around one month past B-band maximum
may be an indication of rapid cooling by active carbon monoxide (CO) formation,
which requires a low temperature and high density environment. These
peculiarities point to an AGB progenitor near the end of its evolution and the
core degenerate scenario as the likely explosion mechanism for LSQ14fmg.Comment: 22 pages, 15 figures, accepted for publication in Ap
The first 48: Discovery and progenitor constraints on the Type Ia supernova 2013gy
We present an early-phase -band light curve and visual-wavelength spectra
of the normal Type Ia supernova (SN) 2013gy. The light curve is constructed by
determining the appropriate S-corrections to transform KAIT natural-system -
and -band photometry and Carnegie Supernova Project natural-system -band
photometry to the Pan-STARRS1 -band natural photometric system. A Markov
Chain Monte Carlo calculation provides a best-fit single power-law function to
the first ten epochs of photometry described by an exponent of
and a time of first light of MJD
56629.4, which is days (i.e., ~hr)
before the discovery date (2013 December 4.84 UT) and
days before the time of -band maximum (MJD 56648.5). The estimate of
the time of first light is consistent with the explosion time inferred from the
evolution of the Si II 6355 Doppler velocity. Furthermore, discovery
photometry and previous nondetection limits enable us to constrain the
companion radius down to . In addition to our early-time
constraints, we use a deep +235 day nebular-phase spectrum from Magellan/IMACS
to place a stripped H-mass limit of . Combined, these
limits effectively rule out H-rich nondegenerate companions
Asymptomatic neurocognitive disorders in patients infected by HIV: fact or fiction?
Neurocognitive disorders are emerging as a possible complication in patients infected with HIV. Even if asymptomatic, neurocognitive abnormalities are frequently detected using a battery of tests. This supported the creation of asymptomatic neurocognitive impairment (ANI) as a new entity. In a recent article published in BMC Infectious Diseases, Magnus Gisslén and colleagues applied a statistical approach, concluding that there is an overestimation of the actual problem. In fact, about 20% of patients are classified as neurocognitively impaired without a clear impact on daily activities. In the present commentary, we discuss the clinical implications of their findings. Although a cautious approach would indicate a stricter follow-up of patients affected by this disorder, it is premature to consider it as a proper disease. Based on a review of the data in the current literature we conclude that it is urgent to conduct more studies to estimate the overall risk of progression of the asymptomatic neurocognitive impairment. Moreover, it is important to understand whether new biomarkers or neuroimaging tools can help to identify better the most at risk population
Supernova 2008J: early time observations of a heavily reddened SN 2002ic-like transient
We provide additional observational evidence that some Type Ia supernovae
(SNe Ia) show signatures of circumstellar interaction (CSI) with hydrogen-rich
material. Early phase optical and near-infrared (NIR) light curves and
spectroscopy of SN 2008J obtained by the Carnegie Supernova Project are studied
and compared to those of SNe 2002ic and 2005gj. Our NIR spectrum is the first
obtained for a 2002ic-like object extending up to 2.2 m. A published
high-resolution spectrum is used to provide insight on the circumstellar
material (CSM). SN 2008J is found to be affected by 1.9 mag of
extinction and to closely resemble SN 2002ic. Spectral and color comparison to
SNe 2002ic and 2005gj suggests 3.1. Spectral decomposition reveals
the underlying SN emission matches a 1991T-like event and, since SN 2008J is as
luminous as SN 2005gj ( 20.3 mag), we conclude that their
CSI emissions are similarly robust. The high-resolution spectrum reveals narrow
emission lines produced from un-shocked gas characterized by a wind velocity of
50 km s. We conclude that SN 2008J best matches an explosion of a
SN Ia that interacts with its CSM.Comment: 8 pages, 4 figures, minor changes to match the published versio
The DECam Local Volume Exploration Survey Data Release 2
We present the second public data release (DR2) from the DECam Local Volume Exploration survey (DELVE). DELVE DR2 combines new DECam observations with archival DECam data from the Dark Energy Survey, the DECam Legacy Survey, and other DECam community programs. DELVE DR2 consists of similar to 160,000 exposures that cover >21,000 deg(2) of the high-Galactic-latitude ( divide b divide > 10 degrees) sky in four broadband optical/near-infrared filters (g, r, i, z). DELVE DR2 provides point-source and automatic aperture photometry for similar to 2.5 billion astronomical sources with a median 5 sigma point-source depth of g = 24.3, r = 23.9, i = 23.5, and z = 22.8 mag. A region of similar to 17,000 deg(2) has been imaged in all four filters, providing four-band photometric measurements for similar to 618 million astronomical sources. DELVE DR2 covers more than 4 times the area of the previous DELVE data release and contains roughly 5 times as many astronomical objects. DELVE DR2 is publicly available via the NOIRLab Astro Data Lab science platform
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