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I built this page to display some of my projects.
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Natural Bridge State Resort Park, Corbin, Kentucky, May 2018

Nuclear Physics

The Large Hadron Collider (LHC) at CERN and the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory have the ability to collide heavy nuclei, such as those of gold and uranium, at nearly the speed of light, reaching temperatures of trillions of degrees Celcius. These laboratories have provided evidence of the formation of an exotic state of matter, called the quark-gluon plasma (QGP). It only exists for a brief amount of time after such collisions and instantly freezes out into a plethora of new particles, which carry the signatures we can use to deduct QGP properties. It reportedly behaves like an almost perfect quantum fluid with no resistance and exhibits other interesting properties.

One of the methods to probe the properties of this matter is by analyzing the conversion of the beam-direction energy at the time of collision into transverse energy after the collision. This analysis is generally done by using data from the calorimeters placed around the collision site. Under Dr. Christine Nattrass in the Relativistic Heavy Ion Physics (RHIP) group at the University of Tennessee (UT), I am developing C++ codes for a method to perform the transverse energy analysis by using tracking detectors instead of the conventional calorimeters.

This method involves a manipulation of the transverse momentum spectra, utilizing the mathematical tools pertaining to heavy-ion collision physics, to calculate the transverse energy production. Due to the limited capabilities of the detectors, however, there is a lack of available data points corresponding to low and high momenta. I use the Boltzmann-Gibbs blast wave function to perform a regression on the available data points and extract the good-fit parameters and other statistics to extrapolate the given spectrum into the low- and high- momentum regions. CERN's ROOT, an object-oriented framework for large-scale data analysis, comes handy in this regard. The codes are located in the Transverse Energy Analysis Git repository.

Before joining the RHIP group, I worked under Dr. Alfredo Galindo-Uribarri at the Physics Division in Oak Ridge National Laboratory in projects related to the study of the decay of the uranium nucleus through the resulting (anti)neutrino signal. About a trillion neutrinos pass through our bodies every second, unnoticed. They are so difficult to detect because they only interact by the nuclear weak force and the even weaker gravity. Very sensitive detectors have to be built to detect them, and clever algorithms and statistical approaches have to be devised to study the noisy signals. I did a literature review of the performance of scintilaltion materials at low temperatures and presented it in a seminar at UT. I also attended a data analysis workshop at Yale Wright Laboratory and assisted in the assembly of the liquid scintillator detector system for the PROSPECT collaboration.

Below are some pictures (click to read descriptions) that show glimpses of my work followed by links to some of the relevant document.

Red curve shows the Boltzmann-Gibbs blast wave functional fit on the transverse momentum spectrum for lambda particles identified by the STAR detector for 19.6 GeV collisions (10-15% central, i.e., slightly off from being head-on) of gold nuclei. Parameters extracted from the chi-square goodness-of-fit test, as well as other statistics, are shown in the box on the top right.

Parallel coordinates plot for 270 diffrent spectra relating 6 different identified particles (color-coded) to their respective collision centrality classes, good-fit parameters, and the transverse energy calculated using said parameters

Average transverse energy per charged particle produced (per unit pseudorapidity) as a function of the number of nucleon participants for different collision energies

Comparison of the normalized transverse energy as a function of collision energy with results from the PHENIX experiment calorimetry

$Topping up PROSPECT photomultiplier tube housing with mineral oil to reduce loss of incoming light due to refraction; Wright Laboratory, Yale University, summer 2017$

LINK -> Particle Physics and Astro-Cosmology Seminar talk on "Survey of the performance of scintillation materials at low temperatures."

Astrophysics

Under Dr. Thomas Pannuti at the Astrophysics Resarch Laboratory in Morehead State University, I studied supernova remnants and nearby galaxies using archival data from the Chandra X-ray Observatory. I used the standard protocol developed for Chandra data analysis to apply different calibrations to the raw data, subtract backgrounds from the observed X-ray sources, and perform spatially-resolved spectral analysis to determine the chemical composition and the nature of the physical processes responsible for the emitted radiation. I discovered sources of X-ray in nearby galaxies, and by analyzing the observations of the same locations in the sky at different periods of time as well as by telescopes sensitive to different frequencies of light (X-ray, infrared, radio), I classified the sources into categories such as binary stars, supernova remnants, background galaxies and background galaxy clusters.

In the summer of 2013, I received the DAAD-RISE (German Academic Exchange Service – Research Internships in Science and Engineering) scholarship to work with the Dark Energy Team at the Argelander-Institut für Astronomie in Bonn, Germany. We studied the dynamical disturbance in the cores of galaxy clusters by measuring the offset between the X-ray emission center and the location of the Brightest Cluster Galaxy or the weak lensing center. Measurement of the offsets is useful in validating the assumption of hydrostatic equilibrium used in, for instance, the estimation of the cluster mass.

44 discrete X-ray sources detected from four different <i> Chandra </i> observations of the nearby galaxy NGC 7793, overlayed on the background of an infrared image of the same galaxy. Among the 44 objects are 39 soft (magenta) and 21 hard (blue) X-ray sources, 15 of which emitted both soft and hard X-rays. 8 of these 15 sources were determined to be supernova remnant candidates and 7 to be X-ray binary candidates. Detection of these sources involved using a tool called 'wavdetect' from the <i> Chandra </i> analysis library. It implements a Mexican Hat wavelet-based source detection algorithm that estimates a local background around a putative source, checks to see if the signal being seen in the pixel is significantly higher than expected, and iteratively tests a hypothesis that the observed signal can be obtained as a fluctuation from the background.

Subtracting 'flares' (caused by high-energy cosmic rays) from the image data to obtain a 'good time interval' of observation for subsequent analysis

Color-color scatter plot of all the X-ray sources that were also detected in infrared observations of the galaxy NGC 45. The axes represent the log ratios of fluxes measured by two different pairs of channels on the Infrared Array Camera (IRAC) on Spitzer. The green circles correspond to the X-ray sources located outside of the visual extent of NGC 45, the red stars correspond to the X-ray sources located within the visual extent of NGC 45, and the blue stars correspond to the radio sources detected by our <a href='http://iopscience.iop.org/article/10.1088/0004-6256/150/3/91/meta'>(Pannuti et al. 2015)</a> radio observations that were also detected by IRAC. The wedge <a href='http://iopscience.iop.org/article/10.1086/432894/meta'> (Lacy et al. 2005) </a> on the top-right encloses sources that are within the field of view covered by NGC 45 but are actually extragalactic in origin and probably background galaxies.

Space Systems

I contributed in the preliminary calibration of the payload on board the cubesat Cosmic X-ray Background Nanosatellite - 2 (CXBN-2) that was deployed on 16 May 2017 from the International Space Station. I used beta decay signals from radioisotopes to test the performance of the off-the-shelf X-ray detector, a Cadmium-Zinc-Telluride semiconductor array, at several different energies relevant to the science mission's goal of studying the cosmic X-ray background at the 30-50 keV range. Based on the amount of radiation the spacecraft would receive in space, I helped the principle investigator, Dr. Ben Malphrus at Morehead State University (MSU), make choice of the orbit, and by estimating the rate of the data that would be collected by the detector arrays, I helped the ground operations team make decisions about the methods and the frequency of data downlink. I represented the science mission during the Preliminary Design Review of the project with NASA and external reviewers and demonstrated compliance of the science mission objectives and operations with the spacecraft systems constraints.

From August 6-11, 2014, Bob Kroll and I used the 21 meter Space Tracking Antenna (STA) at Morehead State University to exchange telemetry between NASA's abandoned ISEE-3 spacecraft and the unofficial and crowdfunded ISEE-3 Reboot project. The ISEE-3 Wikipedia page has more details about the reboot effort.

Summary of the chain of events in the operation of the CXBN-2 mission (screenshot of a slide from the Preliminary Design Review)

Histogram of the CZT array measurement of 122.06 keV and 136.47 keV photons from Cobalt-57 gamma emissions with tungsten fluorescence at 59.32 keV and 67.24 keV

Photo taken by NASA astronaut Peggy Whitson from inside the International Space Station cupola: CXBN-2 (left) and IceCube cubesats are deployed by the NanoRacks deployer (foreground).

Result from preliminary analysis showing response of illuminated (only one, using a collimator) and unilluminated pixels.

Screenshot of a tweet posted on 8 August 2014 during ISEE-3 telemetry exchange. Top left: MSU 21-m STA as seen from the control room. Top and bottom right: ISEE-3 signals detected by the STA. Bottom left: Bob Kroll tracking the satellite from the control room at the MSU Space Science Center

Other Projects

Under the mentorship of Dr. James Masterson in the Department of Government at Morehead State University, I conducted a literature review on the military modernization of the Peoples' Republic of China. I concluded the following:

"The decade-long (2000s) double-digit economic growth has definitely allowed People’s Republic of China to utilize financial, and the resulting technical, resources to evaluate its military prowess and transform its bulk force into a smaller, more efficient army. The world scenario following the 9-11 attacks and the consequent war on terrorism that acted as distraction to world superpowers, on the other hand, has provided China with an unprecedented opportunity to carry out a thorough modernization of its military force without having to care much about the associated international scrutiny and its possible impacts. China seems to have made proper use of these opportunities and has shown that it is capable to plan and then implement suitable strategies -- both in expansion and operation. Even though the PLA has achieved several milestones in due course of time, it still has some inherent defects, primarily its reliance on foreign technology, its inexperience in modern hi-tech warfare and its lagging behind in efficiency, as compared to its regional and international rivals, at the grass-root level. That said, PRC’s potential to rise to an even higher power echelon backed by its future growth in economy cannot be neglected. In any case, China still has a lot to achieve in order to get even close to the military prowess of the United States, and the process of its military modernization is unlikely to result to any major conflict with the potential to fuel a war."

I also worked on the n+k queens separation problem under Dr. Robin Blankenship in MSU Math Department.

LINK -> Research paper on "Military Modernization of China""

Selected Publications/Presentations

“Chandra and Very Large Array Observations of the Nearby Sd Galaxy NGC 45,” Pannuti, Sharma, et al., 2015, The Astronomical Journal, August 2015, Volume 150, Number 3 doi:10.1088/0004-6256/150/3/91

“Radio-continuum study of the nearby sculptor group galaxies. Part 3: NGC 7793 at λ=12.2, 6 and 3 cm,” Pannuti, Sharma, et al., 2014, Astrophysics and Space Science, October 2014, Volume 353, Issue 2, pp 603-611 doi:10.1007/s10509-014-2051-3

Sharma, B. and Pannuti, T. G., “Observations of the Nearby Sculptor Group Galaxy NGC 7793 Made with Chandra X-ray Observatory,” 2014, American Astronomical Society Kentucky Area Meeting, University of Kentucky, Lexington, KY, 3 May 2014 Link

Sharma, B. et al., “Composition of Solutions for the n+k Queens Separation Problem,” 2013, Shenandoah Undergraduate Mathematics and Statistics Conference (SUMS), James Madison University, Harrisonburg, Virginia, September 28, 2013 Link (alt)

Sharma, B. and Doria, A., “Studying the Dynamical Disturbance in Galaxy Clusters Cores through Analysis of Chandra X-ray Observations,” 2013, German Academic Exchange Service - Research Internships in Science and Engineering (DAAD-RISE) and RISE Professional annual scholars meeting, University of Heidelberg, Heidelberg, Germany, July 4-6, 2013; also presented, after getting results, at the Argelander-Institut für Astronomie (AIfA), Bonn, in a dark energy seminar Link (AIfA Talk)

Masters Thesis (in progress): “Transverse Energy Analysis of Relativistic Heavy Ion Collisions through the use of Identified Particles Spectra,” 2018, University of Tennessee, Knoxville, Tennessee

Bachelors Thesis: Senior Thesis Presentation>

Contact

Email: biswas[dot]emails[at]gmail[dot]com