Women of Arecibo: Dr. Tapasi Ghosh

This post is part of our ongoing Women of Arecibo series, which highlights the achievements and experiences of women who built their careers around the 305-meter telescope at Arecibo Observatory, as well as the professional and personal impact of losing an instrument which was of utmost importance in their careers.

The following post features Dr. Tapasi Ghosh, who has been a Staff Scientist at the Green Bank Observatory since 2018. Previously, she worked as a Staff Astronomer at NAIC/Arecibo Observatory from 1992 - 2018. We asked her about her work with Arecibo and the impact of the facility.

How did you become a radio astronomer/work at Arecibo?

Dr. Ghosh on the platform of
Arecibo in 2012

I was born and brought up in Kolkata India, and did my Masters in Physics from the University of Calcutta. Then, in 1983, I went to the Indian Institute of Science in Bangalore to join their "Joint Astronomy Program" for my graduate studies.

I worked for my PhD with scientists/mentors from the radio astronomy group of the Tata Institute of Fundamental Research, and mostly used a radio telescope in a city called, Ooty, in southern India. After completing that, in 1990, I went to The Netherlands for a Postdoctoral Fellowship at Astron, home of the WSRT/JIV-ERIC (although, it was called, Netherlands Foundation for Research in Astronomy (NFRA), in those days). At that point, I married an astronomer from the UK, Dr. Chris Salter (whom I met in India in the late 1980s). Chris was working at the National Radio Astronomy Observatory (NRAO)/ Green-Bank site at that time in 1991. That led us to look for jobs together, and we were hired at Arecibo just as the Gregorian upgrade of the Arecibo Telescope was beginning. It was a marvelous place to work there then, as many new things were happening, and we were happy to be part of a big/wonderful story.

Tell us about the first time you saw Arecibo. How did you feel? What did you see?
When I first arrived at the telescope, it was evening, dark, and there was no dome or the visitor center then. The lookout area was just outside the control room. I was taken there, and saw the lights along the stairs on the high, telescope platform lit up! It felt like a huge ship in the middle of a dark, vast ocean -- the word, "awesome" with its old meaning and full gravity came to mind!

Tell us about your research/work with Arecibo.
My research interest is compact extragalactic radio sources and their atomic and molecular gas content. My technical expertise is in Very-Long-Baseline Interferometry (VLBI) and along with Chris Salter and a few other key personnel, I kept the VLBI equipment up-to-date over the years, commissioned them, and supported all VLBI observations at the Arecibo Observatory. I also provided Radio Frequency Interference (RFI) coordination work, participated in commissioning work of all new post-upgrade Radio astronomy equipment, and even jointly edited the National Astronomy and Ionosphere Center/ Arecibo Observatory (NAIC/AO) newsletter for about 10 years. Every year, I worked with and mentored Research Experiences for Undergraduates (REU) students, and throughout the year, helped visiting astronomers with projects.

Dr. Ghosh (standing- first from the right side) witnessing
the historical moment when she and most of the
astronomy staff at Arecibo were observing Arp220
and they realized that they detected methenamine
for the first time in 2008.

Two of my major science projects were detecting pre-biotic molecules in the galaxy Arp220 and setting the most stringent constraint on the variation of the fundamental constant. In addition, I was a regular active member of a multi-institute team, conducting an all-sky, full-stokes continuum survey using the 7-beam Arecibo L-band Feed Array (ALFA) receiver system, called The G-ALFA Continuum Transient Survey (GALFACTS). The results from that survey are just beginning to be published. The aim of the project was to make a total- and polarized-intensity map at 1.4 GHz, with as yet best angular resolution, generating unprecedented details of the background synchrotron radiation and galactic magnetic field. A simultaneous fast (milli-sec) data-stream allowed the study of the radio transient sky at various time scales.

How did you feel when you heard/learned about the damage to the telescope?
Devastated - most of my (and my husband's, as well as many of my dear friends') life's work was gone -- this is not the way one envisages "leaving the stage"!

What does it mean for the future of your work?
The loss of the Arecibo telescope is felt throughout the radio astronomy community. In planning any new observations, many of us will have to rethink our strategies and some projects may not even be possible to conduct anymore. I still have some Arecibo data to reduce and bring those projects to completion. I am also a co-investigator for a few projects using the Green Bank Telescope. Additionally, as a staff scientist at the Green Bank Observatory, my work of observer’s support, student training, and working with radio astronomical equipment is ongoing.

What does Arecibo mean to you?
Home (and I hope the work will continue in the caring hands of the next generation -- sorry, I am getting sentimental, here).

Who do you see as the next generation of Arecibo users?
The National Science Foundation (NSF) is organizing a public workshop to find that out. Arecibo has been a treasure in the island of Puerto Rico and has inspired generations of young people to pursue scientific careers. So, it will be good if that situation can be maintained while it is (hopefully) re-built for the Radio Scientists’ use to carry out frontline research.

Where do you see yourself in Arecibo's future?
I will participate in the upcoming workshops of NSF to try and see what that future holds. I do have a few ideas, and if I find other people with similar thoughts, maybe, I will be able to make some positive contribution there.