106 research outputs found
Observations and analysis of two type IIP supernovae: the intrinsically faint object SN 2005cs and the ambiguous object SN 2005ay
Aims: To derive observational properties and physical parameters of the
progenitor stars of type IIP supernovae SN 2005ay and SN 2005cs from their
U,B,V,R,I CCD photometry, and to define their velocity behaviour. Methods:
Light curves are analysed, and the velocities and spectral characteristics of
SN 2005cs are obtained using synthetic spectra modeling. Results: Both
supernovae are found to be fainter than the average
SN IIP, with SN 2005cs being more subluminous and showing slight brightening
in the second half of plateau stage in the
V,R,I bands and a low expansion velocity.
The effects of two different plausible distance moduli on the derived
physical parameters of SN 2005ay are considered.
Two approaches are used to recover the amounts of the ejected 56Ni,
indicating masses of the order of
0.02 Msun, although late luminosities might indicate a higher amount for SN
2005ay, especially for the large distance case.
Constraints on the progenitor properties are also presented, based on
empirical analytical models. Two approaches are used to estimate the expansion
velocities at the middle of the plateau phase. SN 2005cs represents an example
of where all 3 physical parameters, velocity, energy and 56Ni mass are lower
than average, a correlation not always observed in SNe IIP. SN 2005ay may
belong to the same class if the shorter distance possibility is adopted.
Furthermore, the estimated mass range for SN 2005cs is in agreement with limits
established by using pre-supernova imaging.Comment: 8 pages, 6 figures, to be published in A&A vol.460, issue 3, December
200
A new small satellite sunspot triggering recurrent standard- and blowout-coronal jets
In this paper,we report a detailed analysis of recurrent jets originated from
a location with emerging, canceling and converging negative magnetic field at
the east edge of NOAA active region AR11166 from 2011 March 09 to 10. The event
presented several interesting features. First, a satellite sunspot appeared and
collided with a pre-existing opposite polarity magnetic field and caused a
recurrent solar jet event. Second, the evolution of the jets showed
blowout-like nature and standard characteristics. Third, the satellite sunspot
exhibited a motion toward southeast of AR11166 and merged with the emerging
flux near the opposite polarity sunspot penumbra, which afterward, due to flux
convergence and cancellation episodes, caused recurrent jets. Fourth, three of
the blowout jets associated with coronal mass ejections (CMEs), were observed
from field of view of the Solar Terrestrial Relations Observatory. Fifth,
almost all the blowout jet eruptions were accompanied with flares or with more
intense brightening in the jet base region, while almost standard jets did not
manifest such obvious feature during eruptions. The most important, the blowout
jets were inclined to faster and larger scale than the standard jets. The
standard jets instead were inclined to relative longer-lasting. The obvious
shearing and twisting motions of the magnetic field may be interpreted as due
to the shearing and twisting motions for a blowout jet eruption. From the
statistical results, about 30% blowout jets directly developed into CMEs. It
suggests that the blowout jets and CMEs should have a tight relationship.Comment: ApJ 18 pages, 7 figure
Hydrogen issue in Core Collapse Supernovae
We discuss results of analyzing a time series of selected
photospheric-optical spectra of core collapse supernovae (CCSNe). This is
accomplished by means of the parameterized supernovae synthetic spectrum (SSp)
code
``SYNOW''.
Special attention is addressed to traces of hydrogen at early phases,
especially for the stripped-envelope SNe (i.e. SNe Ib-c). A thin low mass
hydrogen layer extending to very high ejection velocities above the helium
shell, is found to be the most likely scenario for Type Ib SNe.Comment: 8 pages. Proceedings of the conference ``The Multicoloured Landscape
of Compact Objects and their Explosive Origins'', 2006 June 11--24, Cefalu,
Sicily, to be published by AI
A blowout jet associated with one obvious extreme-ultraviolet wave and one complicated coronal mass ejection event
In this paper, we present a detailed analysis of a coronal blowout jet
eruption which was associated with an obvious extreme-ultraviolet (EUV) wave
and one complicated coronal mass ejection (CME) event based on the
multi-wavelength and multi-view-angle observations from {\sl Solar Dynamics
Observatory} and {\sl Solar Terrestrial Relations Observatory}. It is found
that the triggering of the blowout jet was due to the emergence and
cancellation of magnetic fluxes on the photosphere. During the rising stage of
the jet, the EUV wave appeared just ahead of the jet top, lasting about 4
minutes and at a speed of 458 - \speed{762}. In addition, obvious dark material
is observed along the EUV jet body, which confirms the observation of a
mini-filament eruption at the jet base in the chromosphere. Interestingly, two
distinct but overlapped CME structures can be observed in corona together with
the eruption of the blowout jet. One is in narrow jet-shape, while the other
one is in bubble-shape. The jet-shaped component was unambiguously related with
the outwardly running jet itself, while the bubble-like one might either be
produced due to the reconstruction of the high coronal fields or by the
internal reconnection during the mini-filament ejection according to the
double-CME blowout jet model firstly proposed by Shen et al. (2012b),
suggesting more observational evidence should be supplied to clear the current
ambiguity based on large samples of blowout jets in future studies.Comment: APJ, Accepted October 19, 201
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