2021

Research

In the search of the optical counterpart of compact binary mergers.

See my publications here!

Short Gamma-ray Bursts (SGRB)

We are currently using the Zwicky Transient Facility (ZTF) to follow-up the SGRBs triggers detected by Fermi-GBM. It is thought that compact binary mergers, such as binary neutron star and neutro star - black hole mergers, will produce a short flash gamma-rays, however the error regions derived by the GBM usually span hudred to thousand square degrees, making very challenging to pinpoint the location of the GRB. By targeting the large localization regions with ZTF, we have discovered multiple fast fading transients and assuming energetic properties of the bursts, we have evaluated the efficiency of ZTF.
In this context, I was awarded time at the Gemini observatory during 2021-A to follow-up interesting sources. Our results will be summarized in Ahumada et al. 2021b.

GRB 200826A

On August 26, 2020, we received a short GRB alert and triggered ZTF. Multiple candidates passed our filtering criteria the first night (Sagues-Carracedo et al. 2020) and using the information available the following night we were able to pinpoint the optical afterglow of the short GRB 200826A (Ahumada et al. 2020). We monitored the evolution of this GRB, as its gamma-ray properties suggested a collapsar origin. Using the Gemini North observatory, we discovered an excess in the i-band 28 days later, that could only be explained by an underlying SN, thus despite the GRB duration being short (rest-frame T90 of 0.65 s), our panchromatic follow-up data confirms a collapsar origin. GRB 200826A is the shortest LGRB found with an associated collapsar; it appears to sit on the brink between a successful and a failed collapsar. Our discovery is consistent with the hypothesis that most collapsars fail to produce ultra-relativistic jets.
Our discovery was published in Nature Astronomy: Ahumada et al. 2021
Check out the amazing video and press release that NASA made. There is a version of the video in spanish, which I got to narrate!. NOIRLab and UMD also had a press releases.

Relevant Publications

Authors Title Status
Ahumada et al. 2021 Discovery and confirmation of the shortest gamma ray burst from a collapsar Published in Nature Astronomy
Coughlin, Ahumada et al. 2019 2900 square degree search for the optical counterpart of short gamma-ray burst GRB 180523B with the Zwicky Transient Facility Published in PASP

Gravitational waves

During the third observing run (O3) of LIGO/Virgo, I was part of the ZTF multi-messenger group, led by Prof. Mansi Kasliwal. We used ZTF to scan thousands of squared degrees and follow up hundreds of optical counterpart candidates with numerous facilities around the globe. Our searches led us with numerous articles, mostly constraining the parameter space of the potential KN and the progenitor.

Relevant Publications

Authors Title Status
Anand et al. 2021 Optical follow-up of the neutron star-black hole mergers S200105ae and S200115j Published in Nature Astronomy
Kasliwal, Anand, Ahumada et al. 2021 Kilonova Luminosity Function Constraints based on Zwicky Transient Facility Searches for 13 Neutron Star Mergers Published in ApJ
Andreoni et al. 2019 GROWTH on S190814bv: Deep Synoptic Limits on the Optical/Near-Infrared Counterpart to a Neutron Star-Black Hole Merger Published in ApJ
Coughlin, Ahumada, Anand et al. 2019 GROWTH on S190425z: Searching thousands of square degrees to identify an optical or infrared counterpart to a binary neutron star merger with the Zwicky Transient Facility and Palomar Gattini IR Published in ApJ
Andreoni et al. 2019 GROWTH on S190510g: DECam Observation Planning and Follow-Up of a Distant Binary Neutron Star Merger Candidate Published in ApJ
Goldstein et al. 2019 GROWTH on S190426c: Real-time Search for a Counterpart to the Probable Neutron Star-Black Hole Merger using an Automated Difference Imaging Pipeline for DECam Published in ApJ

Serendipitous Kilonovae search

A compact binary merger with at least a neutron star involved would power a fast fading optical-NIR, known as kilonova. In the absence of a gravitational wave alert or a SGRB trigger, it is still possible to retrieve KN candidates by mining the ZTF stream of data. We have use the ZTF data to constraint the rate of KN independently of GW or SGRB triggers.

Relevant Publications

Authors Title Status
Andreoni et al. 2021 Fast-transient Searches in Real Time with ZTFReST: Identification of Three Optically-discovered Gamma-ray Burst Afterglows and New Constraints on the Kilonova Rate Submitted to ApJ
Andreoni et al. 2021 Constraining the Kilonova Rate with Zwicky Transient Facility Searches Independent of Gravitational Wave and Short Gamma-ray Burst Triggers Published in ApJ

Lensed SN project

To access our database and searches of lensed supernova using LDT click here

Complete publication list

  1. Mohite et al. 2021, ApJ submitted, Inferring kilonova population properties with a hierarchical Bayesian framework I : Non-detection methodology and single-event analyses
  2. Ahumada et al. 2021, Nat. Ast., Discovery and confirmation of the shortest gamma-ray burst from a collapsar
  3. Andreoni et al. 2021, ApJ submitted, Fast-transient Searches in Real Time with ZTFReST: Identification of Three Optically-discovered Gamma-ray Burst Afterglows and New Constraints on the Kilonova Rate
  4. Almualla et al. 2021, MNRAS, Optimizing serendipitous detections of kilonovae: cadence and filter selection
  5. Purdum et al. 2021, ApJ, Time-series and Phase-curve Photometry of the Episodically Active Asteroid (6478) Gault in a Quiescent State Using APO, GROWTH, P200, and ZTF
  6. Stein et al. 2021, Nat. Ast., A tidal disruption event coincident with a high-energy neutrino
  7. Anand, Coughlin et al. 2021, Nat. Ast., Optical follow-up of the neutron star-black hole mergers S200105ae and S200115j
  8. Kasliwal, Anand, Ahumada et al. 2020, ApJ, Kilonova Luminosity Function Constraints Based on Zwicky Transient Facility Searches for 13 Neutron Star Merger Triggers during O3
  9. Andreoni et al. 2020, ApJ, Constraining the Kilonova Rate with Zwicky Transient Facility Searches Independent of Gravitational Wave and Short Gamma-Ray Burst Triggers
  10. Bolin et al. 2020, ApJ, Characterization of Temporarily Captured Minimoon 2020 CD3 by Keck Time-resolved Spectrophotometry
  11. Andreoni et al. 2020, ApJ, GROWTH on S190814bv: Deep Synoptic Limits on the Optical/Near-infrared Counterpart to a Neutron Star-Black Hole Merger
  12. Coughlin, Ahumada, Anand et al. 2019, ApJ, GROWTH on S190425z: Searching Thousands of Square Degrees to Identify an Optical or Infrared Counterpart to a Binary Neutron Star Merger with the Zwicky Transient Facility and Palomar Gattini-IR
  13. Andreoni et al. 2019, ApJ, GROWTH on S190510g: DECam Observation Planning and Follow-up of a Distant Binary Neutron Star Merger Candidate
  14. Goldstein et al. 2019 , ApJ, GROWTH on S190426c: Real-time Search for a Counterpart to the Probable Neutron Star-Black Hole Merger using an Automated Difference Imaging Pipeline for DECam
  15. Coughlin et al. 2019, MNRAS, The Kitt Peak Electron Multiplying CCD demonstrator
  16. Coughlin, Ahumada et al. 2019, PASP, 2900 Square Degree Search for the Optical Counterpart of Short Gamma-Ray Burst GRB 180523B with the Zwicky Transient Facility
  17. Perley et al. 2019, The fast, luminous ultraviolet transient AT2018cow: extreme supernova, or disruption of a star by an intermediate-mass black hole?
  18. Miller, Ahumada et al. 2017, Galaxies, The Extended Baryonic Halo of NGC 3923
  19. 85+ non-refereed publications (GCNs, TNS, etc.)