Workshop 5 - Planning a more robust followup of transient astronomical sources from India

Abstract: Transients are rapidly fading astronomical events and require excellent coordination among multi-wavelength observational facilities to do front-line research on the underlying astrophysical phenomena. Consortia have been established worldwide to achieve this goal. This one-day workshop proposes to discuss and build up a consortium that will bring expertise from institutes and universities within India (and abroad) under a common platform to do transient research in a coherent fashion using Indian observational facilities.

Rationale: Recent all-sky survey programs such as ZTF, ATLAS, ASAS-SN, etc. discovered several brilliant explosions that have changed our understanding of cosmic fireworks. Detection of Gravitational Waves and Neutrinos from these distant objects along with their multi-wavelength electromagnetic follow-ups have unveiled a new window of transient science, known as multi-messenger astronomy. However, in this era of "Time Domain Astronomy" the transient discovery rate has increased enormously – almost exponentially. The upcoming Vera Rubin Observatory, formerly known as ‘Large Synoptic Survey Telescope’ (LSST) will presumably increase this number even higher. Timescales of some of these new transients are expected to be of few hours, while others may sustain for several days to months and even up to years. Therefore, the existence of different progenitor channels is quite obvious, and their environments may also differ from each other to a large extent. The study of such cosmic catastrophes requires (i) early classifications, as well as (ii) multi-wavelength observations and follow-ups of these newly discovered transients, which further demand excellent coordination among various observational facilities. Several machinery have been developed worldwide in the form of consortiums to discover and monitor new transients (e.g., ZTF, ASAS-SN, ATLAS, GAIA science alert), to do their spectroscopic classifications (e.g., PESSTO), coordinated photometric and spectroscopic follow-ups (e.g., GSP, PESSTO), and to search for EM counterpart of GW (e.g., ENGRAVE). India already has several 1-4 m class ground-based optical/infrared facilities, one space-based X-ray/UV telescope, one world-class Radio telescope operating at low frequency, and a few small telescopes at different places of the country. The 4m International Liquid Mirror Telescope (ILMT) which has recently been commissioned is also generating a wealth of data by surveying a strip of the zenith sky. However, due to the absence of such forums, significant results in transient astronomy based on data obtained from Indian facilities is relatively less. Broadly, the objective of this workshop is to initiate the discussion among transient astronomers within the country to establish a consortium where individuals (observers and theoreticians) working in transient astronomy from different Indian Institutes and Universities will join to do collaborative research. The objectives are as follows:

Objectives: The proposed workshop will mainly focus on:   
The strategy for early classification and follow-up of transients. Sky survey programs have already demonstrated several times that early discovery, spectroscopic classifications, and multi-wavelength observations of transients are capable of probing the composition and structure of the circumstellar medium of a transient, and therefore the nature of the progenitor. In comparison to India, longitudinally most of the present and upcoming survey facilities are located in the other half of the Globe. Therefore, the observational facilities in India will always have the advantage of taking a spectrum of an unknown transient within 12 hours after its discovery. One of the proposed agenda of this workshop will be to work on a strategy for efficient transient follow-up from India. A dedicated Slack Channel can be created to improve this coordination.

Creating a single webpage/repository of transient observations from Indian telescopes. This kind of online facility, commonly known as “Marshall” is maintained by every active transient program. Such web-based interfaces simultaneously provide policies for “data security” as well as “data availability/sharing”. This is also a platform from where the larger community will get information about different transients being observed from different Indian telescopes. Essentially such a facility will help different transient groups within the country to collaborate with each other to work on some interesting transients in the future.

Software development for observation and data analysis to build machinery to achieve systematic coordination among different facilities within India. This is a nontrivial job. The "Target and Observation Manager" software (TOM Toolkit) created by Las Cumbres Observatory (LCO) is a significant development in this regard. This customizable software can be used as a platform to build code to conduct coordinated time-scheduled observations, a common calibration system, an automated web-based big-data analysis facility, etc. A large involvement of software expertise (mainly students) is required to achieve this goal. Several pipelines to perform image subtraction, machine learning based algorithms to identify transients, astrometric and photometric calibrations are under development and testing for the ILMT. These could be used for a larger transient astronomy program with some modifications.

Framework to conduct yearly conferences and capacity-building workshops at different institutions/universities within the country. Such initiatives are required to promote transient science among newcomers, as well as to aware the researcher about the importance of archival data in transient astronomy. These conferences are also essential to strengthen the scientific collaborations between different transient research groups within India and beyond.

Dedicated telescopes and instrumentation for transient science. Multi-wavelength follow-ups are necessary to do front-line research in time-domain astronomy. A dedicated optical/NIR follow-up (both photometric and spectroscopic) facility will be very important to do research in key science areas from India in the LSST era. Back-end instrumentation (like a facility for simultaneous photometry at different bands) will be extremely crucial as well. A large fraction of observing time in this facility can be dedicated to transient observations. In future, a group of small telescopes for transient follow-up can be established throughout India for discovery and follow-ups of new transients.

No. of Expected participants: 50

In short, the proposed workshop will aim to bring changes in the following directions:

Topics for discussionPresent situationProposed for the future
Strategy for follow-up of transientNot present at this moment. Only a few good past campaigns.Prepare a framework for a more effective follow-up program. Setup Slack channel/ Google Group
Creating a single web-based repository for all Indian transient observations.Not present at this moment.Work out key components of such a repository. Outline plans to get this implemented
Software development for coordinated observation and data analysis.Not present at this moment.Prepare a requirements document
Capacity-building workshops and conferences for transients within India.Not present at this moment.Plan organization of at least 1 meeting within a year
Dedicated telescope and Instrumentation for transient science.Not present at this moment.Work out requirements and minimum capabilities of a new facility

Proposer: Rupak Roy1, Kuntal Misra2, P. Sreekumar1, Brijesh Kumar2   
1 Manipal Centre for Natural Sciences, Centre of Excellence, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka - 576104   
2 Aryabhatta Research Institute of Observational Sciences, Nainital, Uttarakhand – 263001