272 research outputs found
Parameterizaion – Simulation – Optimization Approach for Reservoir Operation
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
iPTF13bvn: the first evidence of a binary progenitor for a type Ib supernova
The recent detection in archival Hubble Space Telescope images of an object at the location of supernova (SN) iPTF13bvn may represent the first direct evidence of the progenitor of a Type Ib SN. The object's photometry was found to be compatible with a Wolf-Rayet pre-SN star mass of ≈11 M⊙. However, based on hydrodynamical models, we show that the progenitor had a pre-SN mass of ≈3.5 M⊙ and that it could not be larger than ≈8 M⊙. We propose an interacting binary system as the SN progenitor and perform evolutionary calculations that are able to self-consistently explain the light curve shape, the absence of hydrogen, and the pre-SN photometry. We further discuss the range of allowed binary systems and predict that the remaining companion is a luminous O-type star of significantly lower flux in the optical than the pre-SN object. A future detection of such a star may be possible and would provide the first robust identification of a progenitor system for a Type Ib SN.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
Late-time H/He-poor circumstellar interaction in the normal-looking type-Ic supernova SN 2021ocs: an exposed oxygen-magnesium layer and extreme stripping of the progenitor
Supernova (SN) 2021ocs was discovered in the galaxy NGC 7828 within the
interacting system Arp 144, and subsequently classified as a normal type-Ic SN
around peak brightness. VLT/FORS2 observations in the nebular phase at 150 d
reveal that the spectrum is dominated by oxygen and magnesium emission lines of
different transitions and ionization states: O I, [O I], [O II], [O III], Mg I,
and Mg II. Such a spectrum has no counterpart in the literature, though it
bears a few features similar to those of some interacting type Ibn and Icn SNe.
Additionally, SN 2021ocs showed a blue color, mag, after
the peak, atypical for a type-Ic SN. Together with the nebular spectrum, this
suggests that SN 2021ocs underwent late-time interaction with an H/He-poor
circumstellar medium (CSM), resulting from the pre-SN progenitor mass loss
during its final 1000 days. The strong O and Mg lines and the absence of
strong C and He lines suggest that the progenitor star's O-Mg layer is exposed,
which places SN 2021ocs as the most extreme case of massive progenitor star's
envelope stripping in interacting SNe, followed by type-Icn (stripped C-O
layer) and Ibn (stripped He-rich layer) SNe. This is the first time such case
is reported in the literature. SN 2021ocs emphasizes the importance of
late-time spectroscopy of even seemingly normal SNe, which reveals the inner
ejecta and progenitor star's mass loss history.Comment: 9 pages, 5 figures, submitte
PS15cey and PS17cke: prospective candidates from the Pan-STARRS Search for kilonovae
Time domain astronomy was revolutionized with the discovery of the first kilonova, AT2017gfo, in August 2017, which was associated with the gravitational wave signal GW170817. Since this event, numerous wide-field surveys have been optimizing search strategies to maximize their efficiency of detecting these fast and faint transients. With the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), we have been conducting a volume-limited survey for intrinsically faint and fast-fading events to a distance of D ≃ 200 Mpc. Two promising candidates have been identified from this archival search, with sparse data - PS15cey and PS17cke. Here, we present more detailed analysis and discussion of their nature. We observe that PS15cey was a luminous, fast-declining transient at 320 Mpc. Models of BH-NS mergers with a very stiff equation of state could possibly reproduce the luminosity and decline but the physical parameters are extreme. A more likely scenario is that this was an AT2018kzr-like merger event. PS17cke was a faint and fast-declining event at 15 Mpc. We explore several explosion scenarios of this transient including models of it as a NS-NS and BH-NS merger, the outburst of a massive luminous star, and compare it against other known fast-fading transients. Although there is uncertainty in the explosion scenario due to difficulty in measuring the explosion epoch, we find PS17cke to be a plausible kilonova candidate from the model comparisons
iPTF13bvn: the first evidence of a binary progenitor for a type Ib supernova
The recent detection in archival Hubble Space Telescope images of an object at the location of supernova (SN) iPTF13bvn may represent the first direct evidence of the progenitor of a Type Ib SN. The object's photometry was found to be compatible with a Wolf-Rayet pre-SN star mass of ≈11 M⊙. However, based on hydrodynamical models, we show that the progenitor had a pre-SN mass of ≈3.5 M⊙ and that it could not be larger than ≈8 M⊙. We propose an interacting binary system as the SN progenitor and perform evolutionary calculations that are able to self-consistently explain the light curve shape, the absence of hydrogen, and the pre-SN photometry. We further discuss the range of allowed binary systems and predict that the remaining companion is a luminous O-type star of significantly lower flux in the optical than the pre-SN object. A future detection of such a star may be possible and would provide the first robust identification of a progenitor system for a Type Ib SN.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat
GW190425: Pan-STARRS and ATLAS coverage of the skymap and limits on optical emission associated with FRB190425
GW190425 is the second of only two binary neutron star (BNS) merger events to
be significantly detected by the LIGO-Virgo- Kagra gravitational wave
detectors. With a detection only in LIGO Livingston, the skymap containing the
source was large and no plausible electromagnetic counterpart was found in real
time searching in 2019. Here we summarise our ATLAS and Pan-STARRS wide-field
optical coverage of the skymap beginning within 1 hour and 3 hours respectively
of the GW190425 merger time. More recently, a potential coincidence between
GW190425 and a fast radio burst FRB 190425 has been suggested, given their
spatial and temporal coincidence. The smaller sky localisation area of FRB
190425 and its dispersion measure have led to the identification of a likely
host galaxy, UGC 10667 at a distance of 141 +/- 10 Mpc. Our optical imaging
covered the galaxy 6.0 hrs after GW190425 was detected and 3.5 hrs after the
FRB 190425. No optical emission was detected and further imaging at +1.2 and
+13.2 days also revealed no emission. If the FRB 190425 and GW190425
association were real, we highlight our limits on kilonova emission from a BNS
merger in UGC 10667. The model for producing FRB 190425 from a BNS merger
involves a supramassive magnetised neutron star spinning down by dipole
emission on the timescale of hours. We show that magnetar enhanced kilonova
emission is ruled out by optical upper limits. The lack of detected optical
emission from a kilonova in UGC 10667 disfavours, but does not disprove, the
FRB-GW link for this source.Comment: Submitted to MNRAS, 20th Sept 2023, 9 page
Unprecedented early flux excess in the hybrid 02es-like type Ia supernova 2022ywc indicates interaction with circumstellar material
We present optical photometric and spectroscopic observations of the
02es-like type Ia supernova (SN) 2022ywc. The transient occurred in the
outskirts of an elliptical host galaxy and showed a striking double-peaked
light curve with an early excess feature detected in the ATLAS orange and cyan
bands. The early excess is remarkably luminous with an absolute magnitude , comparable in luminosity to the subsequent radioactively-driven second
peak. The spectra resemble the hybrid 02es-like SN 2016jhr, that is considered
to be a helium shell detonation candidate. We investigate different physical
mechanisms that could power such a prominent early excess and rule out massive
helium shell detonation, surface Ni distribution and ejecta-companion
interaction. We conclude that SN ejecta interacting with circumstellar material
(CSM) is the most viable scenario. Semi-analytical modelling with MOSFiT
indicates that SN ejecta interacting with M of CSM at a
distance of cm can explain the extraordinary light curve. A
double-degenerate scenario may explain the origin of the CSM, either by
tidally-stripped material from the secondary white dwarf, or disk-originated
matter launched along polar axes following the disruption and accretion of the
secondary white dwarf. A non-spherical CSM configuration could suggest that a
small fraction of 02es-like events viewed along a favourable line of sight may
be expected to display a very conspicuous early excess like SN 2022ywc.Comment: Accepted to ApJL after minor revisio
The luminous type Ia supernova 2022ilv and its early excess emission
We present observations and analysis of the host-less and luminous type Ia
supernova 2022ilv, illustrating it is part of the 2003fg-like family, often
referred to as super-Chandrasekhar (Ia-SC) explosions. The ATLAS light curve
shows evidence of a short-lived, pulse-like early excess, similar to that
detected in another luminous type Ia supernova (SN 2020hvf). The light curve is
broad and the early spectra are remarkably similar to SN 2009dc. Adopting a
redshift of for SN 2022ilv based on spectral matching, our
model light curve requires a large Ni mass in the range
M, and a large ejecta mass in the range M. The
early excess can be explained by fast-moving SN ejecta interacting with a thin,
dense shell of circumstellar material close to the progenitor (
cm), a few hours after the explosion. This may be realised in a
double-degenerate scenario, wherein a white dwarf merger is preceded by
ejection of a small amount ( M) of hydrogen and
helium-poor tidally stripped material. A deep pre-explosion Pan-STARRS1 stack
indicates no host galaxy to a limiting magnitude of . This implies
a surprisingly faint limit for any host of , providing further
evidence that these types of explosion occur predominantly in low-metallicity
environments.Comment: Accepted to ApJL after minor revisio
SN 2022jli: a type Ic supernova with periodic modulation of its light curve and an unusually long rise
We present multi-wavelength photometry and spectroscopy of SN 2022jli, an
unprecedented Type Ic supernova discovered in the galaxy NGC 157 at a distance
of 23 Mpc. The multi-band light curves reveal many remarkable
characteristics. Peaking at a magnitude of , the high-cadence
photometry reveals 12.5day periodic undulations superimposed on the
200 day supernova decline. This periodicity is observed in the light curves
from nine separate filter and instrument configurations with peak-to-peak
amplitudes of 0.1 mag. This is the first time that repeated periodic
oscillations, over many cycles, have been detected in a supernova light curve.
SN 2022jli also displays an extreme early excess which fades over 25
days followed by a rise to a peak luminosity of erg
s. Although the exact explosion epoch is not constrained by data, the
time from explosion to maximum light is 59 days. The luminosity can
be explained by a large ejecta mass (M)
powered by Ni but we find difficulty in quantitatively modelling the
early excess with circumstellar interaction and cooling. Collision between the
supernova ejecta and a binary companion is a possible source of this emission.
We discuss the origin of the periodic variability in the light curve, including
interaction of the SN ejecta with nested shells of circumstellar matter and
neutron stars colliding with binary companions.Comment: Accepted in ApJ
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