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Nihar Gupte

@nihar-gupte.bsky.social

220 followers 100 following 36 posts

PhD student at the Max Planck for Gravitational Physics in Potsdam and University of Maryland. Working on ML for Gravitational waves and astrophysical populations. Trying to summarize that papers I read

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Nihar Gupte @nihar-gupte.bsky.social · Nov 22

Now that I’m here let show off my poster! In this paper we found evidence for eccentricity in Binary Black holes observed by LIGO-Virgo-KAGRA. You can read the paper here: arxiv.org/abs/2404.14286 and my Twitter summary here: x.com/nihar_gupte/...

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Reposted by Nihar Gupte

Phil Lynch @physlynch.bsky.social · 26d

New paper on the arXiv today about systematic errors when modelling the gravitation waveform from extreme mass ratio inspirals and their impact on LISA data science

Huge thanks to my collaborators, especially Hassan Khalvati, for getting this project over the line! 🧪⚛️🔭🧮

arxiv.org/abs/2509.08875

A posting on the arXiv preprint server.

Title: Systematic errors in fast relativistic waveforms for Extreme Mass Ratio Inspirals

Authors: Hassan Khalvati, Philip Lynch, Ollie Burke, Lorenzo Speri, Maarten van de Meent, Zachary Nasipak

Abstract: Accurate modeling of Extreme Mass-Ratio Inspirals (EMRIs) is essential for extracting reliable information from future space-based gravitational wave observatories. Fast waveform generation frameworks adopt an offline/online architecture, where expensive relativistic computations (e.g. self-force and black hole perturbation theory) are performed offline, and waveforms are generated rapidly online via interpolation across a multidimensional parameter space. In this work, we investigate potential sources of error that result in systematic bias in these relativistic waveform models, focusing on radiation-reaction fluxes. Two key sources of systematics are identified: (i) the intrinsic inaccuracy of the flux data, for which we focus on the truncation of the multipolar mode sum, and (ii) interpolation errors from transitioning to the online stage. We quantify the impact of mode-sum truncation and analyze interpolation errors by using various grid structures and interpolation schemes. For circular orbits in Kerr spacetime with spins larger than a≥0.9, we find that ℓmax≥30 is required for the necessary accuracy. We also develop an efficient Chebyshev interpolation scheme, achieving the desired accuracy level with significantly fewer grid points compared to spline-based methods. For circular orbits in Kerr spacetimes, we demonstrate via Bayesian studies that interpolating the flux to a maximum global relative error that is equal to the small mass ratio is sufficient for parameter estimation purposes. For 4-year long quasi-circular EMRI signals with SNRs=O(100) and mass-ratios 10^−4−10^−6, a global relative error of 10−6 yields mismatches <10^−3 and negligible parameter estimation biases.

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Reposted by Nihar Gupte

Carl Rodriguez @carlrodriguez.bsky.social · Aug 26

Ok, there's a lot of cool stuff in the new @ligo.org collaboration paper (and I'll let the actual LVK members talk about most of it), but one very cool thing from the populations paper (arxiv.org/abs/2508.18083) that jumps out to me is this plot of the effective spin for 30-40 solar mass BHs: 🔭🧪

top panel of figure 13 from the LVK populations paper (linked in post)

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Nihar Gupte @nihar-gupte.bsky.social · Aug 26

Everyone is saying it looks like a phoenix I feel like it looks more like a butterfly or a moth from a top down view

The beak of the phoenix/antenna of the moth is the heaviest one we've seen so far, and by a good bit!

LIGO Scientific Collaboration @ligo.org · Aug 26

Results from the first part of our fourth LIGO @egovirgo.bsky.social KAGRA observing run are out today!

We're pleased to share the largest catalog of gravitational-wave observations with more discoveries of black holes and neutron stars

📰 arxiv.org/abs/2508.18082

🔭🧪⚛️☄️ #GWTC4

New masses in the stellar graveyard plot, showing astronomical observations of black holes and neutron stars. The number of gravitational-wave observations of black holes is overwhelming. The plot is arranged to look nice, the horizontal axis has no meaning, but the vertical one shows masses. We have a significant range of masses from about 1 solar mass to over 200 solar masses for our largest merger remnant. New out today is a neutron star black hole binary GW230518_125908, as well as a lot of binary black holes.

Nihar Gupte @nihar-gupte.bsky.social · Jul 17

An interesting talk today at #gramaldi #amaldi16 by Gautam Satishchandran on how black holes cause decoherence of quantum experiments. The research is a thought experiment but also provides estimates on the decoherence time as a function of the distance between the experiment and the black hole.

Nihar Gupte @nihar-gupte.bsky.social · Jul 17

My favorite slide of the day from #gramaldi #amaldi16. Isobel Romero-Shaw talks about how we can use spin distributions and eccentricities to differentiate between field triples, isolated binary evolution and dynamical formation. It was a cool artwork as well

Nihar Gupte @nihar-gupte.bsky.social · Jul 15

My favorite slide today from Oliver Jennrich at #gramaldi #amaldi16. It shows how rich gravitational waves from extreme mass ratio inspirals are for testing general relativity

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Reposted by Nihar Gupte

LIGO Scientific Collaboration @ligo.org · Jul 14

We are excited to announce the discovery of #GW231123, a gravitational-wave signal from the merger of two high-mass black holes to form one about 190–265 times the mass of our Sun

ligo.org/ligo-virgo-k...

#O4IsHere 🔭🧪☄️

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Nihar Gupte @nihar-gupte.bsky.social · Jun 5

Trump has decided he wants to kill one of humanity's most sensitive instruments for understanding the universe for... about the cost of... half a fighter jet (or less). Source: www.nasa.gov/wp-content/u...

Reposted by Nihar Gupte

SXS Collaboration @sxs-collaboration.bsky.social · May 20

We are excited to release a major update to our catalog of binary black hole simulations, available at arxiv.org/abs/2505.13378! Such simulations are key to LIGO/Virgo/KAGRA being able to extract science from their gravitational wave detections.

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🧪⚛️🔭

Figure 1 from our new catalog paper. We accurately capture precession, memory, eccentricity, and high mass ratio systems. For full details, see the paper.

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Reposted by Nihar Gupte

Christopher Berry @cplberry.bsky.social · May 1

For those with an artistic streak, #GR24Amaldi16 will be hosting an art science exhibition.

We welcome submissions inspired by the themes of the meeting (gravity, cosmology, black holes, gravitational waves, astrophysics). Anyone can submit!

uofgravity.github.io/amaldi-art/

🧪🔭🐚

Amaldi Art Show

uofgravity.github.io

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Nihar Gupte @nihar-gupte.bsky.social · Mar 22

This will help inform astronomers who want point their electromagnetic telescopes towards the merger! You can read the full paper here: www.nature.com/articles/s41...

Real-time inference for binary neutron star mergers using machine learning - Nature

Analysis of gravitational waves from merging binary neutron stars was accelerated using machine learning, enabling full low-latency parameter estimation and enhancing the potential for multi-messenger...

www.nature.com

Nihar Gupte @nihar-gupte.bsky.social · Mar 22

Wanted to shout out this paper: by @maximiliandax.bsky.social and @stephenrgreen.bsky.social. It allows us to perform parameter inference of binary neutron stars in a second. These binary neutron stars are measured with gravitational waves! Here’s a poster I made for the LVK meeting in Barcelona!

Poster showing neutron stars and the remnant kilonova. It also shows the posterior distribution of the neutron star parameters.

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Reposted by Nihar Gupte

Claire Lamman @clairelamman.bsky.social · Mar 20

...so is it time to throw a funeral for LCDM? That depends on who you ask 😂. It's certainly a sign that DESI's DR1 results were not a statistical fluke. Even if LCDM prevails, SOMETHING is weird and that's a great sign that we're learning something new.

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Nihar Gupte @nihar-gupte.bsky.social · Feb 24

GOAT meets GOAT to create the GOAT of Astro YouTube series

Richard McElreath 🐈‍⬛ @rmcelreath.bsky.social · Feb 24

Part 2 is out! Continue with the epic story of how basic trigonometry (and very precise measurement) establishes the scale of the cosmos. This is much more soothing than whatever else you are scrolling. www.youtube.com/watch?v=hFMa...

Nihar Gupte @nihar-gupte.bsky.social · Feb 4

Wow!

Emily Hunt @emily.space · Feb 4

A very fascinating paper went up on the arXiv today!

Jesse Han & El-Badry et al. reanalysed the 21 known 'hypervelocity' stars in the #milkyway.

They find strong evidence that the LMC (Large Milky/Magellanic Cloud) has a supermassive black hole at its core! 🤯 arxiv.org/abs/2502.00102

A figure from the paper (Figure 4). It shows the locations of known hypervelocity stars as black circles, with the predicted overdensity that the LMC would cause shown in red. Full caption:

Predicted on-sky overdensity of hypervelocity stars originating from a 6 × 105M⊙ supermassive black hole in the
LMC. The black open circles denote the Galactic coordinates of hypervelocity stars detected in the HVS Survey, while the
grey-shaded regions mark areas excluded from the survey. The current position of the LMC is illustrated with a representative
image, and its orbital trajectory is drawn with a red arrow. The forward model incorporating an SMBH in the LMC along with
the selection effects of the HVS Survey predicts a prominent overdensity of HVS in the region enclosed by the red contours. The
overdensity arises because stars are boosted in the direction of the LMC’s orbit. This model accurately reproduces the observed
overdensity location, supporting the hypothesis of an SMBH in the LMC as a source of these stars.

Reposted by Nihar Gupte

Annalena Kofler @annalenakofler.bsky.social · Jan 14

1/ 🌌 New Paper Alert: How can we decode the atmospheres of exoplanets efficiently and reliably?
The latest work by my amazing collaborator @timothygebhard.bsky.social introduces Flow Matching Posterior Estimation for atmospheric retrieval. 🚀🧵👇
#AI #MachineLearning #Physics #Astronomy #AcademicSky

Scientific poster with the title "Flow Matching for Atmospheric Retrieval of Exoplanets: Where Reliability meets adaptive noise levels". The background is dark with a blue exoplanet in the center and the surface of a yellow star at the bottom.

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Nihar Gupte @nihar-gupte.bsky.social · Jan 12

I had the opportunity to answer questions at the Royal Astronomical Society (@royalastrosoc.bsky.social) about GWs+ML. Thanks to all the organizers from Royal Holloway (esp. Ann and Mattia) for inviting me!

I was able to work on this fountain pen sketch of the Victoria statue before the workshop: