7 research outputs found
Constraining the X-ray - Infrared spectral index of second-timescale flares from SGR1935+2154 with Palomar Gattini-IR
The Galactic magnetar SGR1935+2154 has been reported to produce the first
known example of a bright millisecond duration radio burst (FRB 200428) similar
to the cosmological population of fast radio bursts (FRBs), bolstering the
association of FRBs to active magnetars. The detection of a coincident bright
X-ray burst has revealed the first observed multi-wavelength counterpart of a
FRB. However, the search for similar emission at optical wavelengths has been
hampered by the high inferred extinction on the line of sight. Here, we present
results from the first search for second-timescale emission from the source at
near-infrared wavelengths using the Palomar Gattini-IR observing system in
J-band, made possible by a recently implemented detector read-out mode that
allowed for short exposure times of 0.84 s with 99.9% observing efficiency.
With a total observing time of 12 hours (47728 images) on source, we place
median limits on the second-timescale emission of mJy (13.1
AB mag). We present non-detection limits from epochs of four simultaneous X-ray
bursts detected by the Insight-{\it HXMT} and {\it NuSTAR} telescopes during
our observing campaign. The limits translate to an extinction corrected fluence
limit of Jy ms for an estimated extinction of mag. These
limits provide the most stringent constraints to date on the fluence of flares
at frequencies of Hz, and constrain the ratio of the
near-infrared (NIR) fluence to that of coincident X-ray bursts to . Our observations were sensitive enough to easily detect
a near-infrared counterpart of FRB 200428 if the NIR emission falls on the same
power law as that observed across its radio to X-ray spectrum. The
non-detection of NIR emission around the coincident X-ray bursts constrains the
fluence index of the brightest burst to be steeper than .Comment: 10 pages, 4 figures, submitted to ApJL. Comments welcom
A Sensitive Search for Supernova Emission Associated with the Extremely Energetic and Nearby GRB 221009A
We report observations of the optical counterpart of the long gamma-ray burst
(LGRB) GRB 221009A. Due to the extreme rarity of being both nearby () and highly energetic ( erg), GRB
221009A offers a unique opportunity to probe the connection between massive
star core collapse and relativistic jet formation across a very broad range of
-ray properties. Adopting a phenomenological power-law model for the
afterglow and host galaxy estimates from high-resolution Hubble Space Telescope
imaging, we use Bayesian model comparison techniques to determine the
likelihood of an associated SN contributing excess flux to the optical light
curve. Though not conclusive, we find moderate evidence
() for the presence of an additional component arising
from an associated supernova, SN 2022xiw, and find that it must be
substantially fainter ( 67% as bright at the 99% confidence interval) than
SN 1998bw. Given the large and uncertain line-of-sight extinction, we attempt
to constrain the supernova parameters (, ,
and ) under several different assumptions with respect to the
host galaxy's extinction. We find properties that are broadly consistent with
previous GRB-associated SNe: - ,
- , and - . We note that these properties are weakly
constrained due to the faintness of the supernova with respect to the afterglow
and host emission, but we do find a robust upper limit on the of
. Given the tremendous range in isotropic
gamma-ray energy release exhibited by GRBs (7 orders of magnitude), the SN
emission appears to be decoupled from the central engine in these systems.Comment: 18 pages, accepted to ApJL, 4 tables, 5 figures. Updated abstract in
Previe
Probing pre-supernova mass loss in double-peaked Type Ibc supernovae from the Zwicky Transient Facility
Eruptive mass loss of massive stars prior to supernova (SN) explosion is key
to understanding their evolution and end fate. An observational signature of
pre-SN mass loss is the detection of an early, short-lived peak prior to the
radioactive-powered peak in the lightcurve of the SN. This is usually
attributed to the SN shock passing through an extended envelope or
circumstellar medium (CSM). Such an early peak is common for double-peaked Type
IIb SNe with an extended Hydrogen envelope but is uncommon for normal Type Ibc
SNe with very compact progenitors. In this paper, we systematically study a
sample of 14 double-peaked Type Ibc SNe out of 475 Type Ibc SNe detected by the
Zwicky Transient Facility. The rate of these events is ~ 3-9 % of Type Ibc SNe.
A strong correlation is seen between the peak brightness of the first and the
second peak. We perform a holistic analysis of this sample's photometric and
spectroscopic properties. We find that six SNe have ejecta mass less than 1.5
Msun. Based on the nebular spectra and lightcurve properties, we estimate that
the progenitor masses for these are less than ~ 12 Msun. The rest have an
ejecta mass > 2.4 Msun and a higher progenitor mass. This sample suggests that
the SNe with low progenitor masses undergo late-time binary mass transfer.
Meanwhile, the SNe with higher progenitor masses are consistent with
wave-driven mass loss or pulsation-pair instability-driven mass loss
simulations.Comment: Submitted to ApJ. Comments are welcome. arXiv admin note: text
overlap with arXiv:2210.0572
SRGA J181414.6-225604: A new Galactic symbiotic X-ray binary outburst triggered by an intense mass loss episode of a heavily obscured Mira variable
We present the discovery and multi-wavelength characterization of SRGA
J181414.6-225604, a Galactic hard X-ray transient discovered during the ongoing
SRG/ART-XC sky survey. Using data from the Palomar Gattini-IR survey, we
identify a spatially and temporally coincident variable infrared (IR) source,
IRAS 18111-2257, and classify it as a very late-type (M7-M8), long period
( days) and luminous () O-rich Mira donor
star located at a distance of kpc. Combining
multi-color photometric data over the last years, we show that the
IR counterpart underwent a recent (starting days before the X-ray
flare) enhanced mass loss (reaching M
yr) episode resulting in an expanding dust shell obscuring the
underlying star. Multi-epoch follow-up from Swift, NICER and NuSTAR reveal a
day long X-ray outburst reaching a peak luminosity of erg s, characterized by a heavily absorbed
( cm) X-ray spectrum consistent with
an optically thick Comptonized plasma. The X-ray spectral and timing behavior
suggest the presence of clumpy wind accretion together with a dense ionized
nebula overabundant in silicate material surrounding the compact object.
Together, we show that SRGA J181414.6-225604 is a new symbiotic X-ray binary in
outburst, triggered by an intense dust formation episode of a highly evolved
donor. Our results offer the first direct confirmation for the speculated
connection between enhanced late-stage donor mass loss and active lifetimes of
the symbiotic X-ray binaries.Comment: 32 pages, 15 figures, Accepted for publication in Ap
A search for relativistic ejecta in a sample of ZTF broad-lined Type Ic supernovae
The dividing line between gamma-ray bursts (GRBs) and ordinary stripped-envelope core-collapse supernovae (SNe) is yet to be fully understood. Observationally mapping the variety of ejecta outcomes (ultra-relativistic, mildly-relativistic or non-relativistic) in SNe of Type Ic with broad lines (Ic-BL) can provide a key test to stellar explosion models. However, this requires large samples of the rare Ic-BL events with follow-up observations in the radio, where fast ejecta can be probed largely free of geometry and viewing angle effects. Here, we present the results of a radio (and X-ray) follow-up campaign of 16 SNe Ic-BL detected by the Zwicky Transient Facility (ZTF). Our radio campaign resulted in 4 counterpart detections and 12 deep upper limits. None of the events in our sample is as relativistic as SN 1998bw and we constrain the fraction of SN 1998bw-like explosions to (3 Gaussian equivalent), a factor of smaller than previously established. We exclude relativistic ejecta with radio luminosity densities in between erg s Hz and erg s Hz at d since explosion for of the events in our sample. This shows that SNe Ic-BL similar to the GRB-associated SN 1998bw, SN 2003lw, SN 2010dh, or to the relativistic SN 2009bb and iPTF17cw, are rare. Our results also exclude an association of the SNe Ic-BL in our sample with largely off-axis GRBs with energies erg. The parameter space of SN2006aj-like events (faint and fast-peaking radio emission) is, on the other hand, left largely unconstrained and systematically exploring it represents a promising line of future research
Probing pre-supernova mass loss in double-peaked Type Ibc supernovae from the Zwicky Transient Facility
International audienceEruptive mass loss of massive stars prior to supernova (SN) explosion is key to understanding their evolution and end fate. An observational signature of pre-SN mass loss is the detection of an early, short-lived peak prior to the radioactive-powered peak in the lightcurve of the SN. This is usually attributed to the SN shock passing through an extended envelope or circumstellar medium (CSM). Such an early peak is common for double-peaked Type IIb SNe with an extended Hydrogen envelope but is uncommon for normal Type Ibc SNe with very compact progenitors. In this paper, we systematically study a sample of 14 double-peaked Type Ibc SNe out of 475 Type Ibc SNe detected by the Zwicky Transient Facility. The rate of these events is ~ 3-9 % of Type Ibc SNe. A strong correlation is seen between the peak brightness of the first and the second peak. We perform a holistic analysis of this sample's photometric and spectroscopic properties. We find that six SNe have ejecta mass less than 1.5 Msun. Based on the nebular spectra and lightcurve properties, we estimate that the progenitor masses for these are less than ~ 12 Msun. The rest have an ejecta mass > 2.4 Msun and a higher progenitor mass. This sample suggests that the SNe with low progenitor masses undergo late-time binary mass transfer. Meanwhile, the SNe with higher progenitor masses are consistent with wave-driven mass loss or pulsation-pair instability-driven mass loss simulations
Characterizing the Ordinary Broad-lined Type Ic SN 2023pel from the Energetic GRB 230812B
International audienceWe report observations of the optical counterpart of the long gamma-ray burst (LGRB) GRB 230812B, and its associated supernova (SN) SN 2023pel. The proximity () and high energy ( erg) make it an important event to study as a probe of the connection between massive star core-collapse and relativistic jet formation. With a phenomenological power-law model for the optical afterglow, we find a late-time flattening consistent with the presence of an associated SN. SN 2023pel has an absolute peak -band magnitude of mag (about as bright as SN 1998bw) and evolves on quicker timescales. Using a radioactive heating model, we derive a nickel mass powering the SN of , and a peak bolometric luminosity of . We confirm SN 2023pel's classification as a broad-lined Type Ic SN with a spectrum taken 15.5 days after its peak in band, and derive a photospheric expansion velocity of at that phase. Extrapolating this velocity to the time of maximum light, we derive the ejecta mass and kinetic energy . We find that GRB 230812B/SN 2023pel has SN properties that are mostly consistent with the overall GRB-SN population. The lack of correlations found in the GRB-SN population between SN brightness and for their associated GRBs, across a broad range of 7 orders of magnitude, provides further evidence that the central engine powering the relativistic ejecta is not coupled to the SN powering mechanism in GRB-SN systems