Optical counterparts of Pulsars, detections and observations.
This project’s goal is to study the optical emission of pulsars both with respect to their spectral properties and with respect to their polarization properties in those wavelengths. To do that, a first step is to create a catalog of optical counterparts to the already detected radio pulsars (Manchester et. al. 2004 +).
On this note, I have searched the PANSTARRS-1 catalog for counterparts given the ephemerids of the pulsars in the ATNF catalog. A map of the spatial distribution (in galactic corrdinates) of the 18 preliminarly detected pulsars follows:
Spatial distribution of the preliminarly detected pulsars in galactic coordinates. Red denotes millisecond pulsars.
Polarimetry with PASIPHAE
Polarimetry, as the name suggests, is the science of measuring the light’s polarization. The most significant quantitative measure of polarization is the degree of polarization (DOP or p). DOP, in simple words, measures the portion of light that is polarized. Based on that quantity, light can be polarized p=100%, partially polarized 0%<p<100% or unpolarized p=0%.
Polarimetry with PASIPHAE will be achieved using 2 cutting-edge-technology polarimeters named WALOP (Wide Area Linear Optical Polarimeter). One will be installed in the Skinakas’ 1.3m telescope and the other in SAAO’s 1m telescope. Both will have a field of view of 30×30 arcminutes and will be able to carry out S/N>3 measurements for stars brighter than 16th magnitude in exposures of 20 minutes. This corresponds to an accuracy in DOP of 0.1%.
The instruments are currently under construction in IUCAA. The optical design is being carried-out by me and Siddharth Maharana, mostly using the ZEMAX platform. We are also running lab tests on the optical elements, to ensure the quality of the instruments. The electronics controller to be used is the IUCAA’s IDSAC controller. The mechanical design of the instrument is carried out by IUCAA’s engineers and managed by me and Siddharth. The software for the control of the instrument, both the GUI and the instrument-side software is developed by myself. The expected delivery period for the instruments is the final trimester of 2020.
Spectral-Line mapping of the physical parameters of supernova remnants in our Galaxy.
This project’s goal was to use spectral-line mapping techniques to measure physical parameters for supernova remnants in oure Galaxy. We took advantage of narrow-band imaging as opposed to the classical usage of spectroscopy, thus being able to map the parameters in hand, instead of measuring their values inside a slit. Additionally we produced an automated python pipeline to automatically repeat the analysis. This is a work still in process, so for the time being the following is the only publishable result:
False-color image of the G67.8+0.5 SNR in optical wavelengths. With red we depict Hα 6562.8 Å line, with blue the [SII] 6716.3Å, 6730.7Å lines and with green the [OIII] 5006.8 Å line.
High steady-state column density of I(2P3/2) atoms from I2 photodissociation. Towards parity non-conservation measurements.
Conducted 2014, Published 2016
Steady-state column densities of 1017 cm-2 of I(2P3/2) atoms are produced from photodissociation of I2 vapour at 290.5 K using 5 W of 532 nm laser light. Recombination of the I(2P3/2) atoms at the cell walls is minimized by coating the cell surface with a hydrophobic silane (dimethyldichlorosilane/DMDCS). Operation at room temperature, and at an I2 vapour pressure of ~0.2 mbar, without using a buffer gas, allows relatively low Lorentz and Doppler widths of ~2π × 1.5 (FWHM) and ~2π × 150 (HW at 1/e2) Mrad/s, respectively, at the 52P3/2 -> 52P1/2 M1 transition of atomic iodine at 1315 nm. These high column densities and low linewidths are favorable for parity nonconservation optical rotation measurements near this M1 transition. Furthermore, as the cell is completely sealed, this method of production of high-density 127I(2P3/2) atoms is also compatible with using iodine radioisotopes, such as for the production of high-density 129I(2P3/2).
(a) Schematic of the experimental setup used for the study of atomic iodine production from photodissociation of molecular iodine at 532 nm. (b) The iodine glass cell. (c) The iodine cell with the green photodissociating laser passing through it.