107 research outputs found
Hybrid polygon and hydrodynamic nebula modeling with multi-waveband radiation transfer in astrophysics
We demonstrate the potential for research and outreach of mixed polygon and
hydrodynamic modeling and multi-waveband rendering in the interactive 3-D
astrophysical virtual laboratory Shape. In 3-D special effects and animation
software for the mass media, computer graphics techniques that mix polygon and
numerical hydrodynamics have become common place. In astrophysics, however,
interactive modeling with polygon structures has only become available with the
software Shape. Numerical hydrodynamic simulations and their visualization are
usually separate, while in Shape it is integrated with the polygon modeling
approach that requires no programming by the user. With two generic examples,
we demonstrate that research and outreach modeling can be achieved with
techniques similar to those used in the media industry with the added
capability for physical rendering at any wavelength band, yielding more
realistic radiation modeling. Furthermore, we show how the hydrodynamics and
the polygon mesh modeling can be mixed to achieve results that are superior to
those obtained using either one of these modeling techniques alone.Comment: Astronomy and Computing, 13 pages, 7 figures, in pres
SN 2009ip and SN 2010mc as dual-shock Quark-Novae
In recent years a number of double-humped supernovae have been discovered.
This is a feature predicted by the dual-shock Quark-Nova model where a SN
explosion is followed (a few days to a few weeks later) by a Quark-Nova
explosion. SN 2009ip and SN 2010mc are the best observed examples of
double-humped SNe. Here, we show that the dual-shock Quark-Nova model naturally
explains their lightcurves including the late time emission, which we attribute
to the interaction between the mixed SN and QN ejecta and the surrounding CSM.
Our model applies to any star (O-stars, LBVs, WRs etc.) provided that the SN
explosion mass is ~ 20M_sun which point to the conditions for forming a
Quark-Nova.Comment: 6 pages, 2 figures, 2 tables. Added more discussion and more
predictions of QN signatures in SN 2009ip and SN 2010mc. Accepted for
publication in Research in Astronomy and Astrophysics Journa
Quark-Novae in massive binaries : a model for double-humped, hydrogen-poor, superluminous Supernovae
LSQ14bdq and SN 2006oz are super-luminous, hydrogen-poor, SNe with
double-humped light curves. We show that a Quark-Nova (QN; explosive transition
of the neutron star to a quark star) occurring in a massive binary,
experiencing two Common Envelope (CE) phases, can quantitatively explain the
light curves of LSQ14bdq and SN 2006oz. The more massive component (A) explodes
first as a normal SN, yielding a Neutron Star which ejects the hydrogen
envelope of the companion when the system enters its first CE phase. During the
second CE phase, the NS spirals into and inflates the second He-rich CE. In the
process it gains mass and triggers a Quark-Nova, outside of the CO core,
leaving behind a Quark Star. The first hump in our model is the QN shock
re-energizing the expanded He-rich CE. The QN occurs when the He-rich envelope
is near maximum size (~ 1000R_sun) and imparts enough energy to unbind and
eject the envelope. Subsequent merging of the Quark Star with the CO core of
component B, driven by gravitational radiation, turns the Quark star to a Black
Hole. The ensuing Black Hole accretion provides sufficient power for the second
brighter and long lasting hump. Our model suggests a possible connection
between SLSNe-I and type Ic-BL SNe which occur when the Quark Nova is triggered
inside the CO core. We estimate the rate of QNe in massive binaries during the
second CE phase to be ~ 5x10^(-5) of that of core-collapse SNe.Comment: 7 pages, 3 figures, 1 table. Accepted for publication in MNRAS. See
http://www.quarknova.ca/LCGallery.htmlL for a picture gallery of the QN fits
to other super-luminous and double-humped SN
"Anti-glitches" in the Quark-Nova model for AXPs
In the Quark-Nova model, AXPs are quark stars surrounded by a degenerate
iron-rich Keplerian ring (a few stellar radii away). AXP bursts are caused by
accretion of chunks from the inner edge of the ring following magnetic field
penetration. For bright bursts, the inner disk is prone to radiation induced
warping which can tilt it into counter-rotation (i.e. retrograde). For AXP
1E2259+586, the 2002 burst satisfies the condition for the formation of a
retrograde inner ring. We hypothesize the 2002 burst reversed the inner ring
setting the scene for the 2012 outburst and "anti-glitch" when the retrograde
inner ring was suddenly accreted leading to the basic observed properties of
the 2012 event.Comment: 5 pages. Accepted for publication in Astrophysics and Space Science.
(Companion paper: http://adsabs.harvard.edu/abs/2014Ap%26SS.350..701K
Spectral Analysis of the 13 keV Feature in XTE J1810-197: Implications for AXP Models
During 2003 and 2004 the Anomalous X-Ray Pulsar XTE J1810-197 went through a
series of four bursts. The spectrum in the tail of one of these bursts shows a
strong, significant emission feature ~13 keV, thereby encoding a wealth of
information about the environment surrounding this object. In this paper we
analyse this emission feature considering both cyclotron and atomic emission
processes and weigh our findings against three leading AXP models: the Magnetar
model, Fall-back disk model and the Quark nova model. We find that atomic
emission from Rubidium within a Keplerian ring (15 km from a compact
object of ) is the most consistent scenario with the
observations, supporting the Quark nova model. Cyclotron emission from an
atmosphere a few hundred meters thick also fits the feature well, but is ruled
out on account of its positional coincidence in three separate AXP sources.Comment: 28 pages, 15 figure
Quark-Novae occurring in massive binaries : A universal energy source in superluminous Supernovae with double-peaked light curves
A Quark-Nova (QN, the sudden transition from a neutron star into a quark
star) which occurs in the second common envelope (CE) phase of a massive binary
(Ouyed et al., 2015a&b), gives excellent fits to super-luminous, hydrogen-poor,
Supernovae (SLSNe) with double-peaked light curves including DES13S2cmm, SN
2006oz and LSQ14bdq (http://www.quarknova.ca/LCGallery.html). In our model, the
H envelope of the less massive companion is ejected during the first CE phase
while the QN occurs deep inside the second, He-rich, CE phase after the CE has
expanded in size to a radius of a few tens to a few thousands solar radii, this
yields the first peak in our model. The ensuing merging of the quark star with
the CO core leads to black hole formation and accretion explaining the second
long-lasting peak. We study a sample of 8 SLSNe Ic with double-humped
light-curves. Our model provides good fits to all of these with a universal
explosive energy of 2x10^52 erg (which is the kinetic energy of the QN ejecta)
for the first hump. The late-time emissions seen in iPTF13ehe and LSQ14bdq are
fit with a shock interaction between the outgoing He-rich (i.e second) CE and
the previously ejected H-rich (i.e first) CE.Comment: Accepted for Publication in ApJ, 7 pages, 2 figures, 3 tables
(Original: 4 pages, 1 figure, 1 table), New title, Model applied successfully
to 6 more double-peaked SLSNe. Related papers: arXiv:1505.05764 and
arXiv:1502.06892 . See http://www.quarknova.ca/LCGallery.html for more QN
fits to other double-humped SLSN
The superluminous SN DES13S2cmm as a signature of a Quark-Nova in a He-HMXB system
We show that by appealing to a Quark-Nova (the explosive transition of a
neutron star to a quark star) occurring in an He-HMXB system we can account for
the lightcurve of the first superluminous SN, DES13S2cmm, discovered by the
Dark-Energy Survey. The neutron star's explosive conversion is triggered as a
result of accretion during the He-HMXB second Common Envelope phase. The dense,
relativistic, Quark-Nova ejecta in turn energizes the extended He-rich Common
Envelope in an inside-out shock heating process. We find an excellent fit
(reduced chi^2 of 1.09) to the bolometric light-curve of SN DES13S2cmm
including the late time emission, which we attribute to Black Hole accretion
following the conversion of the Quark Star to a Black hole.Comment: 4 pages, 1 Table, 2 Figures. Published in ApJ. See
http://www.quarknova.ca/LCGallery.html for a picture gallery of the QN fits
to other super-luminous and double-humped SN
Quark-nova compact remnants: Observational signatures in astronomical data and implications to compact stars
Quark-novae leave behind quark stars with a surrounding metal-rich fall-back
(ring-like) material. These compact remnants have high magnetic fields and are
misconstrued as magnetars; however, several observational features allow us to
distinguish a quark star (left behind by a quark-nova) from a neutron star with
high magnetic field. In our model, bursting activity is expected from
intermittent accretion events from the surrounding fall-back debris leading to
X-ray bursts (in the case of a Keplerian ring) or gamma ray bursts (in the case
of a co-rotating shell). The details of the spectra are described by a constant
background X-ray luminosity from the expulsion of magnetic flux tubes which
will be temporarily buried by bursting events caused by accretion of material
onto the quark star surface. These accretion events emit high energy photons
and heat up the quark star and surrounding debris leading to hot spots which
may be observable as distinct blackbodies. Additionally, we explain observed
spectral line features as atomic lines from r-process material and explain an
observed anti-glitch in an AXP as the transfer of angular momentum from a
surrounding Keplerian disk to the quark star.Comment: 6 pages, NS1 talk presented at the Marcel Grossmann Meeting (MG14),
Rome, July 201
The Burn-UD code for the numerical simulations of the Hadronic-to-Quark-Matter phase transition
Burn-UD is a hydrodynamic combustion code used to model the phase transition
of hadronic to quark matter with particular application to the interior of
neutron stars. Burn-UD models the flame micro-physics for different equations
of state (EoS) on both sides of the interface, i.e. for both the ash
(up-down-strange quark phase) and the fuel (up-down quark phase). It also
allows the user to explore strange quark seeding produced by different
processes including DM annihilation inside neutron stars. The simulations
provide a physical window to diagnose whether the combustion process will
simmer quietly and slowly, lead to a transition from deflagration to detonation
or a (quark) core-collapse explosion. Such an energetic phase transition (a
Quark-Nova) would have consequences in high-energy astrophysics and could aid
in our understanding of many still enigmatic astrophysical transients.
Furthermore, having a precise understanding of the phase transition dynamics
for different EoSs could aid further in constraining the nature of the
non-perturbative regimes of QCD in general. We hope that Burn-UD will evolve
into a platform/software to be used and shared by the QCD community exploring
the phases of Quark Matter and astrophysicists working on Compact Stars.Comment: Comments: 13 pages, 3 figures, Proceedings (and Invited talk) at the
COMPACT STARS IN THE QCD PHASE DIAGRAM IV (CSQCD IV), September 26 - 30,
2014, Prerow, Germany (previous CSQCD meetings/proceedings can be found here
http://www.quarknova.ca/CSQCD.html
Quark-Noave in binaries: Observational signatures and implications to astrophysics
The explosive transition of a massive neutron star to a quark star (the
Quark-Nova, QN) releases in excess of ~ 10^52 erg in kinetic energy which can
drastically impact the surrounding environment of the QN. A QN is triggered
when a neutron star gains enough mass to reach the critical value for quark
deconfinement to happen in the core. In binaries, a neutron star has access to
mass reservoirs (e.g. accretion from a companion or from a Common Envelope,
CE). We explain observed light-curves of hydrogen-poor superluminous Supernovae
(SLSNe Ia) in the context of a QN occurring in the second CE phase of a massive
binary. In particular this model gives good fits to light-curves of SLSNe with
double-humped light-curves. Our model suggests the QN as a mechanism for CE
ejection and that they be taken into account during binary evolution. In a
short period binary with a white dwarf companion, the neutron star can quickly
grow in mass and experience a QN event. Part of the QN ejecta collides with the
white dwarf, shocking, compressing, and heating it to driving a thermonuclear
runaway producing a SN Ia impostor (a QN-Ia). Unlike "normal" Type Ia
supernovae where no compact remnant is formed, a QN-Ia produces a quark star
undergoing rapid spin-down providing additional power along with the 56Ni decay
energy. Type Ia SNe are used as standard candles and contamination of this data
by QNe-Ia can infer an incorrect cosmology.Comment: 6 pages, 1 figures, BN3 talk presented at the Marcel Grossmann
Meeting (MG14), Rome, July 201
- …