The universe is a dynamic and unpredictable place filled with explosive and cataclysmic events that are both challenging and exciting to study. The NRT (New Robotic Telescope) project will enable rapid observations of transient phenomena like Gamma Ray Bursts (GRBs), which fade within minutes of occurrence. In the coming decade, we will benefit from an abundance of data from survey telescopes, requiring sensitive and flexible telescopes like the NRT to follow up on discoveries. Additionally, the NRT will collaborate with other facilities to explore multi-messenger alerts, offering new insights into cosmic phenomena.
Supernovae (SNe) are pivotal events in stellar evolution; their catastrophic nature makes them powerful proves of the evolution and life cycle of different types of star.
The term 'supernova' covers a wide, and growing, variety of stellar explosions which can be distinguished according to their explosion mechanisms. The four boxes below summarise the key supernovae of interest to the NRT project, including the 'exotic' subclass which includes new and exciting sources that are predicted to be discovered by the cadences and depths provided by new survey facilities.
Type Ia SNe are used as standardisable candles for cosmic distance measurements and dark energy exploration (Refsdal, S., 1964, MNRAS, 128, 307). SNe research is a key science case for the Liverpool Telescope (LT), evidenced by the abundance of proposal submissions focused on supernova and related phenomena follow-up. The New Robotic Telescope (NRT) project is strategically positioned to investigate various supernova types, including 'exotic' subclasses expected to emerge from forthcoming survey facilities.
Gravitationally lensed supernovae hold promise for probing cosmological parameters such as dark energy content and the expansion history of the universe (Einstein, A., Science, 84, 506, 1936). There's a critical need for high cadence monitoring and confirmation spectroscopy of these sources, with the Vera Rubin Observatory’s Legacy Survey of Space and Time forecast to discover 10s – 100s lensed type Ia SNe (Goldstein, D. A., et al. 2019, ApJS, 243,6). NRT’s key science requirement for rapid response, coupled with its multi-band imaging and spectroscopy capabilities makes it the ideal for facilitating the characterisation of these objects.
In the modern time-domain survey era, the discovery rate of new SNe has soared, unveiling a plethora of phenomena that challenge existing models, such as superluminous supernovae. Nightly-cadence surveys like ZTF and ATLAS are uncovering a population of fast and blue transients, heralding the forthcoming 'faint and fast' era promised by Rubin (Ho, Anna Y. Q., et al., 2023, ApJ, 949, 2). However, comprehensive follow-up remains indispensable for classification of these objects. The NRT's role in providing essential photometric and spectroscopic follow-up for upcoming surveys like the Vera Rubin Observatory's Legacy Survey of Space and Time, is pivotal in bridging these observational gaps and advancing our understanding of supernovae and their cosmological implications.
Gamma-Ray Bursts (GRBs) are the most energetic explosions detected in our Universe and offer
unique
access to regions of extreme physics due to their central black hole engines. GRBs can be used
to
explore ultra-relativistic jets, strong gravity and intense magnetic fields, as well as acting
as
luminous stellar beacons that probe conditions in the early Universe1. GRBs are often split into
two
categories based on the duration of their afterglow emission: long GRBs are thought to be
associated
with the death of massive stars2,3, while short GRBs are believed to be the merger of
two
compact
objects4,5. The GW170817 gravitational wave event confirmed the association of short
GRBs
with
neutron star mergers and further accelerated interest in these sources6.
The Liverpool Telescope’s autonomous and robotic follow-up has been key for GRB
science7,8,9,10.The
rapidly fading nature, particularly of short GRBs, means that traditional telescopes, even those
with large apertures, struggle to catch the source before it has become too faint. The automated
response to NASA Swift triggers, without human intervention, allows the LT to take data within
minutes of outburst11. The LT is a world-leading facility for time domain
astrophysics,
but the
increased sensitivity of new discovery facilities means the fainter targets will require a
larger
aperture optical follow-up facility. The NRT will build on LT’s capabilities with a larger
aperture
and faster response time: obtaining data within 30 seconds of a trigger. This sensitivity and
rapid
response will enable a new generation of transient objects, discovered with facilities such as
SVOM,
to be routinely optically observed during the prompt emission phase for the first time. Robotic
telescopes like LT and NRT are uniquely suited to this task of transient follow-up since they
can
flexibly and automatically react to new discoveries in real time.
1. Piran, 2004, Rev. Mod. Phys. 76, 1143
2. Woosley et al, 1993, ApJ, 405,273
3. MacFadyen and Woosley, 1999, ApJ, 524,1, 262
4. Eichler et al., 1989, Nature, 340, 126
5. Gehrels et al., 2005, Nature, 437, 851
6. Abbott et al., 2017, ApJ, 848, L12
7. Mundell et al., 2007, ApJ, 660, 1, 489
8. Steele et al., 2009, Nature, 462, 7274
9. Mundell et al., 2013, Nature, 504, 119
10. Shrestha et al., 2022, MNRAS, 516, 2, 1584
11. Steele et al., 2004, SPIE, 5489, 679
Multicolour, high cadence imaging
Broadband imaging
Multi-object spectroscopy
Early follow-up of rapid colour evolution in kilonovae (~hrs)
Detection of candidate counterparts
GOTO transient follow-up: RTML/command line triggers
Early-time host galaxy spectra
Polarimetric and photometric monitoring
Candidate flares classification and monitoring
Rapid spectroscopic classification and spectral line ratios
Simultaneous, high-cadence photometry
Non-sidereal tracking with autoguider
Spectroscopy and polarimetry of asteroids
Spectroscopy of comet ices
Ground-based follow-up observations of planet candidates