activity
20112025
most citedImproved upper limits on the 21-cm signal power spectrum of neutral hydrogen at from LOFAR

311 citations · 1.8k across the 22 of their papers we have counts for

collaborators

22 papers

astro-ph.GA2025

RGC-Bent: A Novel Dataset for Bent Radio Galaxy Classification

Mir Sazzat Hossain, Khan Muhammad Bin Asad, Payaswini Saikia +7

We introduce a novel machine learning dataset tailored for the classification of bent radio active galactic nuclei (AGN) in astronomical observations. Bent radio AGN, distinguished…

astro-ph.GA2023★ 2 cited

The SARAO MeerKAT 1.3 GHz Galactic Plane Survey

S. Goedhart, W. D. Cotton, F. Camilo +127

We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251° 358°and 2° 61°at $|b| \le 1.…

astro-ph.IM2023★ 3 cited

Morphological Classification of Radio Galaxies using Semi-Supervised Group Equivariant CNNs

Mir Sazzat Hossain, Sugandha Roy, K. M. B. Asad +4

Out of the estimated few trillion galaxies, only around a million have been detected through radio frequencies, and only a tiny fraction, approximately a thousand, have been manual…

astro-ph.GA2023★ 10 cited

Mining Mini-Halos with MeerKAT I. Calibration and Imaging

K. S. Trehaeven, V. Parekh, N. Oozeer +7

Radio mini-halos are clouds of diffuse, low surface brightness synchrotron emission that surround the Brightest Cluster Galaxy (BCG) in massive cool-core galaxy clusters. In this p…

astro-ph.GA2022★ 137 cited

The 1.28 GHz MeerKAT Galactic Center Mosaic

I. Heywood, I. Rammala, F. Camilo +108

The inner 200 pc region of the Galaxy contains a 4 million M supermassive black hole (SMBH), significant quantities of molecular gas, and star formation and cosmic…

astro-ph.CO2020★ 311 cited

Improved upper limits on the 21-cm signal power spectrum of neutral hydrogen at from LOFAR

F. G. Mertens, M. Mevius, L. V. E Koopmans +23

A new upper limit on the 21-cm signal power spectrum at a redshift of is presented, based on 141 hours of data obtained with the Low-Frequency Array (LOFAR). The an…

astro-ph.CO2020★ 109 cited

Constraining the intergalactic medium at 9.1 using LOFAR Epoch of Reionization observations

R. Ghara, S. K. Giri, G. Mellema +19

We derive constraints on the thermal and ionization states of the intergalactic medium (IGM) at redshift 9.1 using new upper limits on the 21-cm power spectrum measured b…

astro-ph.GA2019★ 125 cited

The 1.28 GHz MeerKAT DEEP2 Image

T. Mauch, W. D. Cotton, J. J. Condon +101

We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one FWHM primary beam area with FWHM resolution and Jy/beam rms nois…

astro-ph.IM2019★ 62 cited

Primary beam effects of radio astronomy antennas -- II. Modelling the MeerKAT L-band beam

K. M. B. Asad, J. N. Girard, M. de Villers +12

After a decade of design and construction, South Africa's SKA-MID precursor MeerKAT has begun its science operations. To make full use of the widefield capability of the array, it…

astro-ph.HE2018★ 161 cited

Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR

F. Camilo, P. Scholz, M. Serylak +205

New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least ear…

astro-ph.IM2017★ 34 cited

Wide-field LOFAR-LBA power-spectra analyses: Impact of calibration, polarization leakage and ionosphere

B. K. Gehlot, L. V. E. Koopmans, A. G. de Bruyn +9

Contamination due to foregrounds (Galactic and Extra-galactic), calibration errors and ionospheric effects pose major challenges in detection of the cosmic 21 cm signal in various…

astro-ph.IM2017★ 36 cited

Polarization leakage in epoch of reionization windows: III. Wide-field effects of narrow-field arrays

K. M. B. Asad, L. V. E. Koopmans, V. Jelić +3

Leakage of polarized Galactic diffuse emission into total intensity can potentially mimic the 21-cm signal coming from the epoch of reionization (EoR), as both of them might have f…

astro-ph.CO2017★ 290 cited

Upper limits on the 21-cm Epoch of Reionization power spectrum from one night with LOFAR

A. H. Patil, S. Yatawatta, L. V. E. Koopmans +25

We present the first limits on the Epoch of Reionization (EoR) 21-cm HI power spectra, in the redshift range , using the Low-Frequency Array (LOFAR) High-Band Antenna (…

astro-ph.IM2016★ 139 cited

Probing Ionospheric Structures using the LOFAR radio telescope

M. Mevius, S. van der Tol, V. N. Pandey +24

LOFAR is the LOw Frequency Radio interferometer ARray located at mid-latitude (). Here, we present results on ionospheric structures derived from 29 LOFAR nighttim…

astro-ph.IM2016★ 37 cited

Polarization leakage in epoch of reionization windows: II. Primary beam model and direction dependent calibration

K. M. B. Asad, L. V. E. Koopmans, V. Jelić +11

Leakage of diffuse polarized emission into Stokes I caused by the polarized primary beam of the instrument might mimic the spectral structure of the 21-cm signal coming from the ep…

astro-ph.GA2015★ 89 cited

Linear polarization structures in LOFAR observations of the interstellar medium in the 3C196 field

V. Jelić, A. G. de Bruyn, V. N. Pandey +21

This study aims to characterize linear polarization structures in LOFAR observations of the interstellar medium (ISM) in the 3C196 field, one of the primary fields of the LOFAR-Epo…

astro-ph.CO2015★ 20 cited

Simulating the 21cm forest detectable with LOFAR and SKA in the spectra of high-z GRBs

B. Ciardi, S. Inoue, F. B. Abdalla +26

We investigate the feasibility of detecting 21cm absorption features in the afterglow spectra of high redshift long Gamma Ray Bursts (GRBs). This is done employing simulations of c…

astro-ph.CO2015★ 2 cited

Polarization leakage in Epoch of Reionization windows: I. LOFAR observations of the 3C196 field

K. M. B. Asad, L. V. E. Koopmans, V. Jelić +25

Detection of the 21-cm signal coming from the epoch of reionization (EoR) is challenging especially because, even after removing the foregrounds, the residual Stokes maps conta…

astro-ph.IM2014★ 25 cited

Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

H. K. Vedantham, L. V. E. Koopmans, A. G. de Bruyn +91

We present radio observations of the Moon between and MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far bey…

astro-ph.GA2014★ 82 cited

Initial LOFAR observations of Epoch of Reionization windows: II. Diffuse polarized emission in the ELAIS-N1 field

V. Jelic, A. G. de Bruyn, M. Mevius +106

This study aims to characterise the polarized foreground emission in the ELAIS-N1 field and to address its possible implications for the extraction of the cosmological 21-cm signal…

astro-ph.CO2014★ 61 cited

Constraining the epoch of reionization with the variance statistic: simulations of the LOFAR case

Ajinkya H. Patil, Saleem Zaroubi, Emma Chapman +27

Several experiments are underway to detect the cosmic redshifted 21-cm signal from neutral hydrogen from the Epoch of Reionization (EoR). Due to their very low signal-to-noise rati…

astro-ph.CO2011★ 24 cited

Discovery of the correspondence between intra-cluster radio emission and a high pressure region detected through the Sunyaev-Zel'dovich effect

C. Ferrari, H. T. Intema, E. Orrù +9

We analyzed new 237 MHz and 614 MHz GMRT data of the most X-ray luminous galaxy cluster, RX J1347-1145. Our radio results are compared with the MUSTANG 90 GHz Sunyaev-Zel'dovich ef…