Nabeel Rehemtulla

I'm a third year Astronomy PhD student in CIERA at Northwestern University working with Prof. Adam A. Miller. I'm working on integrating a machine learning I created called BTSbot into the ZTF Bright Transient Survey workflow to automatically and rapidly identify transients. I will soon also work with the upcoming LS4 survey.

I graduated from the University of Michigan in 2021 and have an ongoing project there with Prof.Monica Valluri. We work with the DESI Milky Way Survey to map the Milky Way's dark matter distribution with a spherical Jeans modeling code I wrote called NIMBLE.

This website serves as a supplement to my CV, containing resources like past presentation slides and posters.

Research Projects

Presentations of these projects can be found below.

BTSbot: A ConvNet to automatically identify ZTF transients

Northwestern University, CIERA

The Bright Transient Survey (BTS) relies on visual inspection ("scanning") to select sources for accomplishing its mission of spectroscopically classifying all bright extragalactic transients found by the Zwicky Transient Facility (ZTF). BTSbot provides a bright transient score to individual ZTF alert packets using their image data and 14 extracted features. BTSbot eliminates the need for scanning by automatically identifying new bright transient candidates. BTSbot outperforms BTS scanners in terms of completeness (99% vs. 95%) and identification speed (on average, 7.4 hours quicker).

Codebase publicly available on GitHub

Presentations & Publications

Presented a poster at the Workshop on ML for Astrophysics at the 40th International Conference on Machine Learning:
Conference proceedings | Poster PDF

Gave an oral talk at the Transients and Variable Universe conference at UIUC:

Non-Parametric Spherical Jeans Mass Estimation with B-Splines

University of Michigan – Ann Arbor

We consider the application of Jeans modeling to mapping the dark matter distribution in the outer reaches of the Milky Way using field halo stars. To do so, we develop a novel non-parametric routine for solving the spherical Jeans equation by fitting B-splines to the velocity and density profiles of halo stars and an MCMC-based subroutine that deconvolves observational effects from the underlying distributions.

Codebase publicly available under the name NIMBLE (Non-parametrIc jeans Mass with B-spLinEs)

Presentations & Publications

Published as Rehemtulla et al. 2022

Presented an iPoster at 237th AAS meeting and won a Chambliss Astronomy Achievement award.
the iPoster | PDF version

Gave an oral talk at the Michigan Institute for Data Science Poster Symposium 2020 and won the Outstanding Undergraduate Poster award.
the poster | the presentation slides

I wrote a short summary of this project (a bite) for the undergraduate research series on

Star Formation Rate in Merger Galaxies

University of Michigan – Ann Arbor
MDM Observatory, Kitt Peak National Observatory

We observe four target merger galaxies in H-alpha to calcualte their star formation rate densities and compile previously observed data giving us their gas surface density. With these two quantities, we can investigate how various merger galaxies stand in relation to non-mergers with respect to the Kennicutt-Schmidt law.

Presentations & Publications

the observing proposal | write-up of findings

Other Projects

Website Architect for GHOSTS HST Survey

University of Michigan & Leibniz Institute for Astrophysics

I undertook a project rebuilding the Galaxy, Halos, Outer disks, Substructure, Thick disks and Star clusters (GHOSTS) HST survey website. I noted inefficiencies in the source of the current version and designed a rebuild to correct for these and improve expandability. I proposed my rebuild project to GHOSTS P.I. Dr. Roelof de Jong with logistical help from GHOSTS team member and UM professor, Eric Bell. My rebuild employs Jinja, an efficient Python templating engine, to simplify the creation and modification of their webpages.

the GitHub repository


When I'm not staring into a jupyter notebook, I like to keep myself moving and trying new things. During quarantine, I starting baking all kinds of desserts. In order to stay fit after eating the desserts, I've taken up indoor rock climbing.

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