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A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.
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Posts
Future Blog Post
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Blog Post number 4
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Blog Post number 1
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personal
Personal
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portfolio
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publications
J021659-044920: a relic giant radio galaxy at z ∼ 1.3
Published in Monthly Notices of the Royal Astronomical Society, 2015
This paper is about the discovery of a relic giant radio galaxy. We studies the radio lobe properties and estimated their age, magnetic field strength.
Recommended citation: Tamhane, P.D. et. al, (2015). "J021659-044920: a relic giant radio galaxy at z ∼ 1.3." MNRAS. 453. https://academic.oup.com/mnras/article/453/3/2438/1078675
Origins of Molecular Clouds in Early-type Galaxies
Published in The Astrophysical Journal, 2019
In this paper we show that the molecular gas in early type galaxies most likely originates from cooling of the hot gas in their atmospheres, and that the thermodynamic properties of early type galaxies are similar to that of cluster center galaxies.
Recommended citation: Babyk, Iu. V., McNamara, B. R., Tamhane, P. D. et. al. (2019). "Origins of Molecular Clouds in Early-type Galaxies." ApJ. 887. https://iopscience.iop.org/article/10.3847/1538-4357/ab54ce
Thermally Unstable Cooling Stimulated by Uplift: The Spoiler Clusters
Published in The Astrophysical Journal, 2020
In this paper we studied clusters with low atmospheric cooling time but no warm/cold gas. We propose that the clusters lack cold gas because their central radio jets fail to lift low-entropy gas to large altitudes.
Recommended citation: C. G. Martz, B. R. McNamara, P. E. J. Nulsen, A. N. Vantyghem, M-J. Gingras, Iu. V. Babyk, H. R. Russell, A. C. Edge, M. McDonald, P. D. Tamhane et. al, (2020). "Thermally Unstable Cooling Stimulated by Uplift: The Spoiler Clusters." ApJ. 897. https://iopscience.iop.org/article/10.3847/1538-4357/ab96cd
Molecular Flows in Contemporary Active Galaxies and the Efficacy of Radio-Mechanical Feedback
Published in Monthly Notices of the Royal Astronomical Society, 2022
We studied molecular flows in brightest cluster galaxies (BCGs) and compared them with molecular flows in early type galaxies. Molecular flows in BCGs powered by radio-mechanical feedback are larger, heavier and slower. We found that radio feedback is generally more effective at lifting gas in galaxies compared to quasars and starburst winds. Star formation in BCGs is quenched compared to other galaxies.
Recommended citation: Prathamesh D. Tamhane, Brian R. McNamara, Helen R. Russell, Alastaire C. Edge, Andrew C. Fabian, Paul E. J. Nulsen, Iurii V. Babyk et. al, (2022). "Molecular Flows in Contemporary Active Galaxies and the Efficacy of Radio-Mechanical Feedback." MNRAS, Volume 516, Issue 1. https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stac2168/6653098
Radio jet-ISM interaction and positive radio-mechanical feedback in Abell 1795
Published in Monthly Notices of the Royal Astronomical Society, 2023
We studied the positive radio mechanical feedback and the interaction between radio jets and the interstellar medium in the brightest cluster galaxy of the Abell 1795 galaxy cluster. We found that radio-jet triggered star formation has a lower efficiency compared to the efficiency of star formation in the central regions of nearby spiral galaxies.
Recommended citation: Prathamesh D. Tamhane, Brian R. McNamara, Helen R. Russell, Francoise Combes, Yu, Qiu, Alastair C. Edge, Roberto Maiolino, Andrew Fabian, Paul E. J. Nulsen, R. Johnstone, Stefano Carniani, (2022). "Radio jet-ISM interaction and positive radio-mechanical feedback in Abell 1795." MNRAS, Volume 519, Issue 3. https://academic.oup.com/mnras/article-abstract/519/3/3338/6965357?redirectedFrom=fulltext
A massive multiphase plume of gas in Abell 2390’s brightest cluster galaxy
Published in Monthly Notices of the Royal Astronomical Society, 2024
We studied the origin of massive (>10^10 solar masses) molecular gas plume in Abell 2390 brightest cluster galaxy also observed in the X-ray and optical wavelengths. We discuss different mechanisms that could have led to the formation of the plume based on its observed properties. We also report detection of molecular gas absorption against the nucleus and somple models to explain its origin.
Recommended citation: Rose, Tom; McNamara, B. R.; Combes, F.; Edge, A. C.; Russell, H.; Salomé, P.; Tamhane, P. ; Fabian, A. C.; Tremblay, G., (2024). "A massive multiphase plume of gas in Abell 2390s brightest cluster galaxy." MNRAS. https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stae213/7581997
Can Active Galactic Nuclei Activity Be Enhanced by Ram Pressure Stripping?—X-Ray Perspective
Published in The Astrophysical Journal, 2025
This study investigated the potential connection between ram pressure stripping (RPS) and active galactic nuclei (AGN) activity in cluster galaxies from an X-ray perspective, analyzing a sample of RPS galaxies in four nearby clusters. The results show no significant enhancement in X-ray AGN activity among RPS galaxies compared to non-RPS galaxies, suggesting that any potential effect is weak or occurs on a short timescale
Recommended citation: Tiwari, Juhi; Sun, Ming; Luo, Rongxin; Fossati, Matteo; Chen Chien-Ting, Chen J.; Tamhane, Prathamesh, (2025). "Can Active Galactic Nuclei Activity Be Enhanced by Ram Pressure Stripping?—X-Ray Perspective." ApJ. https://iopscience.iop.org/article/10.3847/1538-4357/ad9b7f
XRISM Reveals Low Nonthermal Pressure in the Core of the Hot, Relaxed Galaxy Cluster A2029
Published in The Astrophysical Journal Letters, 2025
I co-authored one of the first publications using early data from the XRISM telescope. In this study, we analyzed the extremely massive and relaxed galaxy cluster Abell 2029, one of the XRISM Performance Verification (PV) targets. Using XRISMs high spectral resolution, we measured bulk motions in the intracluster medium below 100 km/s and a velocity dispersion of ~170 km/s. If the dispersion is due to turbulence, it implies that non-thermal pressure contributes only ~3% of the thermal pressure, confirming Abell 2029s remarkably relaxed dynamical state.
Recommended citation: Xrism collaboration et al, (2025). "XRISM Reveals Low Nonthermal Pressure in the Core of the Hot, Relaxed Galaxy Cluster A2029." ApJL. https://iopscience.iop.org/article/10.3847/2041-8213/ada7cd
Velocity Structure Correlations between the Nebular, Molecular, and Atmospheric Gases in the Cores of Four Cool Core Clusters
Published in The Astrophysical Journal, 2025
We analyzed the velocity structure function (VSF), a tool for quantifying turbulence, of nebular gas in the central galaxies of four galaxy clusters using Keck Cosmic Web Imager data, and compared it to molecular gas traced by ALMA. In most systems, the extended filamentary nebular gas shows steep VSF slopes, likely influenced by gravity and AGN-driven motions. Comparisons to X-ray-derived turbulence from Chandra observations support condensation-driven gas motions in some clusters. We also highlighted challenges in comparing VSFs across wavelengths due to instrumental, projection, and resolution-related effects.
Recommended citation: Li, Muzi ; McNamara, B. R.; Coil, Alison L.; Marie-Joëlle Gingras ; Brighenti, Fabrizio; Russell, H. R.; Tamhane, Prathamesh D.; Oh, S. Peng ; Perrotta, (2025). "Velocity Structure Correlations between the Nebular, Molecular, and Atmospheric Gases in the Cores of Four Cool Core Clusters." ApJ. https://iopscience.iop.org/article/10.3847/1538-4357/ad9b7f
research
Research
Molecular flows in Brightest Cluster Galaxies
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talks
Molecular gas flows in active galaxies and the potential impact of radio-mechanical feedback
Published:
I talked about our analysis of molecular gas flows in 14 brightest cluster galaxies. Comparing molecular flows in BCGs to those in other nearby AGN and starburst galaxies, we found that flows in BCGs are larger, heavier and slower. The lifting factor in BCGs is higher than other AGN indicating that the radio-mechanical feedback is more effective. It can also suppress star formation in BCGs.
Radio-jet triggered star formation in a molecular gas flow
Published:
I attended the Star formation in the era of JWST conference in Greece, where I discussed my work on star formation in the molecular gas filament in the central galaxy of the Abell 1795 cluster. The BCG has ~7-10 kpc long molecular gas filaments with bright UV emission indicative of star formation wrapped around radio jets emanating from the central AGN. I presented my results on the interaction between radio jets and the gas, the nature and efficiency of star formation and the role of turbulence.
Fantastic Beasts: Active Galactic Nuclei in Galaxies and Clusters
Published:
I had the pleasure of speaking at the Astronomy on Tap (AoT) event in Huntsville. AoT is a fantastic science outreach program that brings together astronomers and space enthusiasts in informal settings like bars, cafes, and similar venues. These events happen in cities all around the world, where local astronomers share talks, discussions, and presentations on various astronomy topics in a relaxed and engaging way that’s accessible to everyone, regardless of their background.
The impact of gas uplift by cavities in mechanical AGN feedback
Published:
I had the honor of speaking at the McNamara@65 conference at the University of Waterloo in Canada. This event celebrated the 65th birthday of my PhD supervisor, Prof. Brian McNamara, and his significant contributions to astronomy.
Natural Language to SQL for Astronomical Data Access
Published:
I had the honor of speaking at the UniversAI: Exploring the Universe with Artificial Intelligence symposium at the Harokopio University of Athens in Greece.
teaching
PHYS 122L
Undergraduate course, University of Waterloo, 2018
Instructed and supervised undergraduate students in a first-year physics lab course, guiding them through experiments, data analysis, and report writing to reinforce core concepts in mechanics and electromagnetism.
PHYS 270
Undergraduate course, University of Waterloo, 2018
Assisted in teaching a second-year theoretical physics course by leading discussion sections, clarifying complex concepts, and grading assignments and exams.
ECE 105
Undergraduate course, University of Waterloo, 2018
Conducted tutorials for the course, graded student’s assignments and exams, held office hours.
PHYS 175
Undergraduate course, University of Waterloo, 2019
Conducted tutorials for the course, graded student’s assignments and exams, held office hours.
PHYS 121
Undergraduate course, University of Waterloo, 2019
Conducted tutorials for the course, graded student’s assignments and exams, held office hours.
PHYS 132L
Undergraduate course, University of Waterloo, 2020
Instructed and supervised undergraduate students in a first-year physics lab course, guiding them through experiments, data analysis, and report writing to reinforce core concepts in mechanics and electromagnetism.
MNS 201L
Undergraduate course, University of Waterloo, 2020
Instructed and supervised undergraduate students in a second-year physics lab course, guiding them through experiments, data analysis, and report writing to reinforce core concepts in mechanics and electromagnetism.
SCI 238
Undergraduate course, University of Waterloo, 2020
Assisted in teaching an introductory astronomy course for second-year physics students by supporting lectures, answering student questions, and grading assignments.
PHYS 115
Undergraduate course, University of Waterloo, 2021
Conducted tutorials for the course, graded student’s assignments and exams, held office hours.
PHYS 121L
Undergraduate course, University of Waterloo, 2021
Instructed and supervised undergraduate students in a first-year physics lab course, guiding them through experiments, data analysis, and report writing to reinforce core concepts in mechanics and electromagnetism.
PHYS 112L
Undergraduate course, University of Waterloo, 2022
Instructed and supervised undergraduate students in a first-year physics lab course, guiding them through experiments, data analysis, and report writing to reinforce core concepts in mechanics and electromagnetism.
PHYS 112
Undergraduate course, University of Waterloo, 2022
Conducted tutorials for the course, graded student’s assignments and exams, held office hours.
PHYS 111
Undergraduate course, University of Waterloo, 2022
Conducted tutorials for the course, graded student’s assignments and exams, held office hours.