TOM Dev Program

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The goal of this program is to stimulate observational follow-up programs using Target and Observation Manager systems, especially (though not limited to) those using alerts from ZTF and other current surveys, providing the opportunity to prepare to do science with LSST alerts and data products.

Teams with members who attended the TOM Workshop 2019 in Pasadena were able to apply for telescope time the LCO 1m Network, the SOAR 4.1m and Gemini 8m telescopes, as well as for development grants of up to $45,000. A full description of the rules can be found here.

Of the 33 proposals received, the following 15 were selected:

An End-to-End Transient Classification Experiment based on Contextual Information

PI: Adriano Baldeschi, Northwestern University, USA

Time-domain astronomy is the new frontier of Discovery. The improved cadence, sensitivity and wide field of view of the current astronomical surveys has led to the discovery of new types of phenomena that challenge current notions of physics (e.g. Superluminous supernovae or Fast and Blue Optical Transients). Our ability to make discoveries in this current and future era of time-domain astrophysics is limited by a two-pronged challenge: (i) it will be necessary to identify specific targets of interest amidst millions of alerts each night; (ii) we will need very fast identification of notable alerts, ideally within hours of detection, to enable prompt follow-up observations (spectroscopy and/or observations across the spectrum). Thus motivated, we are currently developing a transient classification pipeline designed around a new concept for prompt and effective transient identification/classification that capitalizes on a currently untapped resource: contextual information, i.e. the multi-wavelength properties of the transient’s host galaxy and environment. The main goal of this project is to test of our pipeline in real time.

Probing supernova progenitors with rapid TOM-enabled observations

PI: Andy Howell, Las Cumbres Observatory, USA

We propose to observe lightcurves of four young supernovae in the north and four in the south with the LCO network. Spectroscopy will be obtained with Geminin N and S and SOAR, and supplemented with SOAR. The SNe will be part of the Global Supernova Project, a key project to study hundreds of SNe over several years. We will prioritize SNe within 100 Mpc caught within 24 hours of explosion to look for companion signatures that disappear soon after explosion. We will trigger these observations with SNEx 2.0, built with the TOM Toolkit. In addition we will add new functionality, and make it available to the TOM Toolkit: a discovery explorer, target prioritizer, observing run manager, and streamlined facility triggering.

We Act On Fast: Streamlining Follow-up of Fast Transients

PI: Chien-Hsiu Lee, NSF Optical/IR Laboratory, USA

The advent of ultra-wide camera and all-sky surveys have revolutionized time-domain studies, especially enabling the discovery of very fast evolving supernovae (SNe). This proposal tackles with two aspects to help unveil the nature of these very fast SNe. First, we are seeking observations right after the onset of explosion to shed lights on the progenitors of SNe. Secondly, we are also chasing after rapidly declining SNe, such as SN2018kzr (McBrien et al. 2019). We are only aware of a few cases of these very fast evolving sources, not because they are intrinsically rare, but due to the cadence and selection function employed by ground-based searches optimized to discover type Ia supernovae (SNe Ia) for cosmology. Consequently, studies of these sources are in their infancy, and the astronomical community desperately needs more data to understand them. Our proposal addresses this pressing need by streamlining alert brokers, TOM toolkit, and the network of telescopes within AEON together with the alerts coming from Zwicky Transient Facility (ZTF) and augmented with ATLAS/ASAS-SN/Pan-STARRS when needed. We will efficiently identify SNe early on and chase rapidly declining sources than any previous ground-based surveys; we will use the suite of tools being developed for LSST to build an unmatched observational data-set on these sources for the astronomical community.

Large Scale Bright Supernova Follow-up Coordination

PI: Christoffer Fremling, Caltech, USA

We will perform coordinated LCO 1-m multi-band follow-up of supernovae (SNe) discovered by the public Zwicky Transient Facility (ZTF) Bright Transient Survey (BTS). LCO 1-m observations will be triggered on BTS SNe brighter than 18th mag that are accessible from the southern LCO 1-m telescopes in such a way that LCO data is obtained on nights where ZTF is not be observing. We expect to improve the median lightcurve cadence of bright BTS SNe to 1 day compared to the standard 3 day cadence of the public ZTF northern sky survey. The collected data will be used for SN demographics. We will characterize the lightcurve phase-space of both Type Ia SNe and core-collapse SNe.

We Catch On Fast: Improving Alert Broker’s Ability to Discover Rare Explosive Transients

PI: Gautham Narayan, Illiois University, USA

The real-time classification of transient events is a more complex challenge than retrospective classification because of the need to contend with sparse, low S/N photometry, and the paucity of rare exotic events to build training sets. However, finding such rare and exotic transient events early is vital to probe of the physics of their progenitor systems. Early observations are a unique window into the circumstellar environment before the explosion overruns the material and while the gas is still recombining after being "flash ionized" by the shock breakout. Interaction with a potential companion star is also visible in the first hours. We have built a novel deep-learning algorithm for Real-time Automated Photometric Identification (RAPID) into the ANTARES broker system that is processing the alert stream from the Zwicky Transient Facility (ZTF). We will combine the ZTF data with observations from the Young Supernova Experiment (YSE) to improve our ability to identify exotic transients within hours of explosion. With our ability to identify exotic transients fast, we seek to complement the g- and r-band ZTF photometry with automatically scheduled multi-band LCO imaging, and trigger rapid response spectroscopy through the AEON queuing system. These observations will enable us to model the astrophysics of these sources, and begin to understand their populations and environments.

Discovery and Followup of Active Asteroids in ZTF Alerts

PI: Geza Gyuk, Adler Planetarium, USA

For many years asteroids have been distinguished from comets not only because of their orbits and compositions, but also by their activity. There is a growing understanding, however, that at least some asteroids are dynamic objects, showing signs of activity either as a single event, or more frequently episodically. Active asteroids, as this class has been labelled, appear to be a diverse population driven by a variety of mechanisms including volatile sublimation, direct impacts, rotation driven mass shedding and "exotic" dust creation and ejection processes. To date only around a few dozen active asteroids have been found: estimates of active asteroids cover a wide range in frequency from $10^{-4}$ to as rare as $10^{-6}$. Current and deep future surveys such as ZTF and LSST, however, will almost certainly increase these numbers by orders of magnitudes. We propose using ZTF alerts to look for newly active asteroids among the population of known asteroids. MPC, ALCDEF data and prior ZTF data can establish a baseline light curve, along with the size of regular expected variations to this light curve. Evidence of activity will be found in ZTF alerted deviations from this predicted baseline light curve. We request 100 hours of LCO 1-m time to take confirming photometry of candidate active asteroids. After confirmation with LCO observations asteroid activity triggers will be rapidly disseminated to the community.

Illuminating Gravitational Waves with Rapid, Global and Collaborative Followup

PI: Iair Arcavi, Tel Aviv University, Israel

The discovery of the first gravitational-wave signal from a neutron-star merger in 2017, followed by the first kilonova, initiated the era of gravitational-wave - electromagnetic-wave multi-messenger astronomy. This discovery provided a wealth of insights into many open issues in astrophysics, yet many open questions remain. In this program we aim to use Las Cumbres Observatory imaging to search for the electromagnetic counterpart to a high-probability well-localized gravitational wave event involving a neutron star, and SOAR spectroscopy to vet the candidates. Once the counterpart is found, we will use Las Cumbres Observatory and SOAR to follow the event photometrically and spectroscopically. We also aim to develop new tools to improve the efficiency and transparency of the search and followup campaigns within the TOM Toolkit framework. This coming semester is the perfect opportunity to develop these techniques and a community collaborative culture, ahead of the era of full sensitivity GW detectors (O4 and beyond).

Automatic Follow-up of Optical Counterparts to Gravitational Waves and Short Gamma-ray Bursts

PI: Igor Andreoni, Caltech, USA

The association between short gamma-ray bursts (sGRB), optical kilonovae, and neutron star mergers was spectacularly demonstrated during the follow-up of the gravitational wave (GW) event GW170817. This first joint detection of electromagnetic and GW signals opened a new era for multi-messenger science. The discovery of kilonovae allow us to pin-point of the merger host galaxy, while the light curve and spectra can be used, for example, to infer the content of heavy elements that the merger produced via r-process nucleosynthesis. However, the search for an electromagnetic counterpart is more challenging than ever, with GW signals often detected at large distances (beyond 200Mpc) and with coarse localizations. Many transients are usually found during wide-field follow-up, most of which are slowly-evolving sources unrelated with neutron star mergers. This program will use the LCO 1-m telescope network to identify rapidly-evolving kilonovae via systematic, photometric characterization of the counterpart candidates discovered during GW and sGRB follow-up campaigns.

Towards the Era of Autonomous Astronomy: A program for early supernova studies

PI: Jakob Nordin, Humboldt-Universität zu Berlin, Germany

In this program we will incorporate LCO TOM functionalities into the AMPEL analysis framework. The goal is to create methods that enable immediate, consistent and automized observations of transient sources. We plan to demonstrate the power of such tools through obtaining multi-band lightcurves of ZTF transients starting <~1 day of the initial explosion, with a particular focus on blue wavelengths.

Probing the population of black holes and planets in the Milky Way with microlensing

PI: Markus Hundertmark, University of Heidelberg, Germany

According to Einstein’s theory of General Relativity, matter and energy curve space-time. In case of a sufficiently good alignment of a source star, a lens star, and the observer, multiple images are formed, unresolvable at all wavelengths. This phenomenon is known as Galactic gravitational microlensing. The distorted images lead to an increase in the detected brightness of the source. Galactic velocity dispersion and differential rotation make the brightening a time-dependent effect.
Gravitational microlensing is currently the best method capable of detecting isolated stellar mass black holes, since it is not required to observe the light emitted by the lens. Moreover, the microlensing detection technique is also able to discover planets around low-mass host stars down to Earth mass and reaching even lunar mass range, as well as planets not orbiting a host star at all. In this program, we implement a concerted approach to ingest multiple alert streams, such as the Gaia photometric science alert broker, to follow characterizable planet candidates as well as candidates for lensing black holes on the whole sky. The targets, we are aiming for, are sufficiently bright to be observed with spectroscopic follow-up in order to obtain a comprehensive picture of the limiting factors in the mass and lens distance relation. In order to facilitate follow-up we provide two Telescope Observation Managers (TOMs) dedicated to the long-term monitoring of black holes and short-term response to microlensing planet candidates.

Building a TOM for early classification of type Ia supernovae and managing follow-up

PI: Mi Dai, Rutgers University, USA

This proposal aims at building a customized TOM for identifying type Ia supernovae (SN Ia) early enough to trigger follow-up observations for the SIRAH program and for managing the SIRAH program. The SIRAH program will obtain HST NIR observations of 24 SN Ia in the smooth Hubble flow (0.02<z<0.07). We will develop an early classification pipeline that combines photometry and spectroscopy to identify SN Ia in their early phases (7-10 days before maximum) for triggering HST observations to ensure that the HST observations can be obtained near or soon after maximum light. The proposed observations from LCO and SOAR will be an essential part for the early classification pipeline. Our customized TOM and the proposed observations will be important to the success of the SIRAH program.

Improving TOM Synergies with Community Brokers Proposal Team

PI: Paula Sanchez-Saez, Pontificia Universidad Católica de Chile

The new generation of large etendue survey telescopes have demonstrated a growing need for sophisticated astronomical alert processing systems. In this context, the community has begun development of alert filtering systems known as “Brokers”, which ideally will smoothly connect user-selected samples with automatic follow-up telescopes through Target and Observation Managers (TOMs) to achieve a wide range of science goals. One such community Broker has been developed with the aim to facilitate the study of stationary (non–moving) variable and transient objects. This Broker is currently processing the ZTF alert stream, providing classifications of different variable and transient objects, in preparation to become an official broker for LSST. The overall motivation for this program is to enhance the functionality and interoperability of the Broker for end users, by developing and testing plugins and service interfaces using the TOM Toolkit, for the rapid follow-up of transient and variable sources, and to make the Broker classification stream available for the TOM Toolkit users. Particularly, the scientific cases covered by this proposal include: rapid follow-up of young SNe and novel transients candidates; and follow-up of outlier candidates, changing-state AGN (CSAGN) candidates, and variable stars.

Strongly lensed supernovae as a unique probe of stellar physics and cosmology: A pilot program demonstrating the capabilities of TOM systems

PI: Sherry Suyu, Max Planck Institute for Astrophysics, Germany

We propose ToO photometric and spectroscopic observations of strongly lensed supernovae (SNe) that are necessary to achieve two goals: (1) obtain unprecedented early-phase spectra of SN within days of explosion to shed light on SN progenitors, and (2) measure the cosmic expansion rate (H0), addressing current H0 tensions and paving the way for future lensed SN cosmology. We will use and develop TOM systems to efficiently carry out these follow-up observations. This is a high-gain pilot program that will demonstrate the capabilities of the TOM toolkit for the emerging science case of lensed SNe, especially in the upcoming LSST era.

Strongly lensed supernovae: Time-delays and lensing magnification with ZTF

PI: Suhail Dhawan, Stockholm University, Sweden

The Zwicky Transient Facility is a wide-field time-domain survey designed to discover rare transient phenomena of great scientific interest. One such phenomenon is multiply-imaged Type Ia supernovae (SNe~Ia). The standard luminosity of these supernovae can be used to discover these systems with strong gravitational lensing, independently of image separation. We propose ToO observations with NIRI using ALTAIR-LGS adaptive optics to resolve the multiple-images and measure the time-delays and lensing magnificaion of these systems. From these we can measure the expansion of rate of the universe, shedding light on the current tension between local and global measurements of H$_0$. Moreover, the lensing magnification spectrum of SNIa is an important tool to explore theories of gravity beyond Einstein's general relativity.

TOMs for MOPs Follow-Up

PI: Wesley Fraser, National Research Council of Canada

After the spectacular flybys of Pluto and 2014 MU69, the New Horizons (NH) spacecraft is now in its Kuiper Belt Extended Mission phase (KEM). During KEM, NH is traversing the core of the Kuiper Belt acting as a portable telescope, acquiring photometric observations of nearby Kuiper Belt Objects (KBOs) from within the Kuiper Belt itself. This affords the unique geometry for high phase angle observations, which cannot be gathered by any other facility. While observations from other terrestrial or space based facilities can access phase angles (Observer-Target-Sun angle) of α <2◦, NH can provide observations at right-angle geometries, with 70 <α <120◦. Taken together, the observations at low and high phase angles provide the only means available to us to characterize the micro and macroscopic surface textures of remote Solar System bodies such as KBOs. This is an unprecedented scientific opportunity that has never before been possible, and may never be possible again. But before NH can observe those KBOs, we must first know where those bodies are! This proposal will make use of the flexible imaging facilities at LCO, SOAR, and Gemini to track candidate KEM targets discovered by our on-going KBO discovery programs. The expected results of this program is the identification of a handful of new targets, along with the production of sufficiently accurate ephemerides for KEM observations of those targets.