Download A Proposed Collaboration Between LIGO

A Proposed Collaboration Between LIGO-Virgo and Swift to Improve the
Chances to Detect Gravitational Waves from Core Collapse Supernovae
1
1
Kiranjyot (Jasmine) Gill, Dr. Michele Zanolin
1
With support from Marek Szczepanczyk
1Physics
Department, Embry-Riddle Aeronautical University, Prescott, AZ
Swift X-ray Telescope (XRT)
Overview

Object
Swift XRT = X-ray CCD imaging spectrometer designed to measure
the position, spectrum, and brightness of gamma-ray bursts
(GRBs) and afterglows over a wide dynamic range covering more
than 7 orders of magnitude in flux.

Field of View (‘) = 23.6 x 23.6

+70 short gamma-ray bursts (GRBs) found & sizable fraction = Xray & optical afterglows; a few have been detected in the radio
spectrum.
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Table 1
Angular Size
Distance
Messier 82
11.2 ‘ x 4.3 ‘
3.5-3.8 Mpc
NGC 4565
15.9’ x 1.85’
16.2 Mpc
NGC 6357
1 degree x 1 degree
Canis Major Dwarf Galaxy 12 degrees x 12 degrees
Abstract
48504.34 pc
8584.839 pc
Sampled LIGO Interferometer Noise
Discovered # of GRBs with their associated transients through their
XRT X-Ray light curves.[1]
The Core-Collapse supernovae (CCSNe) mark the dynamic and explosive end of the lives of
massive stars. The mysterious mechanism behind CCSNe explosions could be explained by
detecting the corresponding gravitational wave (GW) emissions by the laser interferometer
gravitational wave observatory, LIGO. GWs are extremely hard to detect because they are
weak signals in a floor of instrument noise. Optical observations of CCSNe are already used in
coincidence with LIGO data, as a hint of the times when to search for the emission of GWs.
More of these hints would be very helpful. For the first time in history a Harvard group has
observed X-ray transients in coincidence with optical CCSNe. This discovery has proven
that even if a supernova had its light absorbed with dust, X-ray transients that are more
penetrating, and thus could be used as a hint on when to search for GWs. The SWIFT satellite
can monitor galaxies with an X-ray probe. SWIFT is interested in collaborating with LIGO. The
main goal of this project will be to quantify the benefits for LIGO by using the SWIFT
satellite to monitor galaxies within 20 Mega parsecs from Earth, because beyond that
assumed distance LIGO is incapable of producing a sensitivity that would allow a GW detection
from CCSNe.
Physical Assumptions and
Constraints
Improvements Provided by
Swift XRT

B= 10^{-20.5 – A/2.5}



Bursts observed by the Beppo-SAX X-ray telescopes detect
GRBs within 6-8 hours by observing the fading X-ray
afterglows.
 By the time the observation is made however, the intensity
has dropped by 4-5 orders of magnitude.
The Swift XRT will begin observations before the GRB ends in
many cases, and will fill in the large time gap during which the
Lorentz factor of the relativistic blast wave changes.







X-ray info gives better time constraints on the emission of
gravitational waves (GW)
From the usage of the XRT, there will be a theorized lower false
alarm rate associated with the data collection.[2]



Whirlpool Galaxy
Andromeda Galaxy


Data base search to evaluate an observational rate for different
survey and bands

Evaluation of E&M information valuable for the GW-triggered
search and the comparison with the theoretical population
synthesis expectation

LIGO-Virgo-SWIFT Conference; Presentation; Discussion and
Evaluation of Swift Satellite usage

Compilation of two documents; one focusing on the
Memorandum of Understanding issued between the LIGO-Virgo
and Swift collaborations while the second paper focuses on the
First Targeted Search for GWB from SN in Coincidence with X-ray
observations from Swift
Sombrero Galaxy
Centaurus A
But, also rare due to intergalactic events such as the absorption of
optical emissions from events such as dust obscuration, which not
only prevents onset detection but interferes with any possible data
collection.
increase detection efficiency of nearby supernovas
surpass 20%[2] factor provided by the optical detector capabilities
Theorized larger portion of SNe that will be found in the x-ray region using the
XRT portion of the Swift Satellite due to the efficient transmission of X-rays.
Milky Way Galaxy
Centaurus A
Currently only 20%[2] of Supernovae (SNe) may be observed
using only the optical range
The X-ray emissions within 20 Mpc will not be absorbed and
thus is correlated to GWs produced in < 20 Mpc.[1]

Rough estimation of 2 SNe per milky way unit mass per century would be discovered
if around 3 SNe per galaxy was discovered
Future Directions
Virgo Super Cluster
Stellar collapses generating a supernova explosion mechanism
itself presents an unlikely possibility.

Blue Luminosity units: erg (which is 10-7 J) s-1
Absolute Magnitude units: parsecs
Correlation between mass of the galactic distributions and their given blue
luminosity (extracted from the Gravitational Wave Catalog reference) =
correlation high = then, blue luminosity is a reasonable substitution for the
mass of galactic distributions
Introducing basic constraints in relation to the potential number of SNe
discovered using the Swift XRT technology
SN per century produced plot = rough estimation may be assumed by
converting the mass into a SN estimation rate we assume:

XRT in Contrast with Optical
Observation

Where B is the blue luminosity of each given galaxy, and A is the absolute
magnitude of each given galaxy.
Curve of galactic distributions within 20 Mpc; maps out Milky Way >
Andromeda Clusterings > Virgo SuperCluster
 Slope of the curve produced optically produces a cubic relationship
nearing the 20 Mpc cutoff distance

References
[1]arXiv:0802.1712v2
[2]arXiv:1306.0559v1
Acknowledgements
Support provided by:
•LVC Organization
•ERAU URI