pith. sign in

arxiv: 2509.14043 · v1 · submitted 2025-09-17 · 🌌 astro-ph.HE

Searching for radio emission from radio quiet magnetars with MeerKAT

Marlon L. Bause , Kamalpreet Kaur , Isabella Rammala-Zitha , Laura G. Spitler This is my paper

Pith reviewed 2026-05-18 16:07 UTC · model grok-4.3

classification 🌌 astro-ph.HE
keywords magnetarsradio quietMeerKATfast radio burstsupper limitsneutron starstime domain searchimaging
0
0 comments X

The pith

Thirteen radio-quiet magnetars yield no radio detections in MeerKAT data but set deep upper limits on flux and pulses.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents MeerKAT observations of 13 radio-quiet magnetars to test for radio emission over multiple epochs. No signals appear in time-domain searches for single pulses across a wide dispersion-measure range or in folded data using X-ray timing, nor in imaging for persistent emission. This supplies quantitative bounds on mean flux density and pulse strength that bear on whether magnetars can produce fast radio bursts. The work also extracts light curves and notes additional sources in the fields. Continued high-cadence radio monitoring independent of X-ray activity is recommended to catch possible intermittent emission.

Core claim

Regular MeerKAT observations of 13 radio-quiet magnetars found no radio emission in the time domain over a DM range of 20–10000 pc cm^{-3} using both a transient search pipeline and folding with X-ray ephemerides. The data yield upper limits of 60 μJy on mean flux density and 39 mJy on single-pulse fluence. Imaging provides additional upper limits on persistent Stokes I and V emission together with light curves for the same 13 sources.

What carries the argument

Dual-domain analysis of MeerKAT interferometer data: time-domain single-pulse search with the TransientX pipeline plus folding on X-ray ephemerides, combined with snapshot imaging for persistent flux and variability limits.

If this is right

  • The non-detections constrain the radio luminosity and duty cycle of radio-quiet magnetars and narrow the parameter space for magnetar models of fast radio bursts.
  • Most magnetars appear to stay radio quiet on timescales of months to years, supporting long-term rather than snapshot monitoring campaigns.
  • Radio searches should proceed independently of X-ray flux levels to catch any rare or state-dependent emission.
  • The imaging limits and light curves supply a baseline for detecting future transient radio activity in the same fields.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If emission is highly sporadic, increasing observation cadence or total time could raise the probability of catching a burst.
  • These flux limits can be folded into population synthesis models to estimate the fraction of magnetars that ever become radio loud.
  • Future wide-field instruments could apply the same dual-domain approach to a larger sample and test whether radio activity correlates with spin-down rate or magnetic-field strength.

Load-bearing premise

Any radio emission from these magnetars falls inside the searched dispersion-measure window and the X-ray ephemerides correctly predict the rotational phase for folding.

What would settle it

A single radio pulse or persistent source from any of the 13 targets with fluence above 39 mJy or mean flux above 60 μJy in comparable MeerKAT or similar observations would falsify the reported non-detection.

Figures

Figures reproduced from arXiv: 2509.14043 by Isabella Rammala-Zitha, Kamalpreet Kaur, Laura G. Spitler, Marlon L. Bause.

Figure 1
Figure 1. Figure 1: Total intensity images of two two magnetars with a SNR association. Left: SGR 1935+2154 at the S1-band, right: 1E1841-054 at L-band. tion: S mean = (S/N)ZTsys G p npoltobsB r X 1 − X FSP = (S/N)Tsys √ w G p npolB , where (S/N) = 7 is the minimal signal to noise ratio of the folded profile or the single pulse respectively, Tsys is the system tem￾perature, G is the gain, npol = 2 is the number of polarisatio… view at source ↗
Figure 3
Figure 3. Figure 3: Over view of the single pulse detections of the pulsar in the Beam of CXOU1647 in an L-band observation. The top row of panels shows (from left to right) a histogram of the detected single pulse widths and S/N respectively as well as S/N vs. DM. The bottom part shows a DM vs. time scatter plot of all candidates, where each axis as a histogram added and the S/N of the candidates are given by the circle size… view at source ↗
Figure 2
Figure 2. Figure 2: Light curves (solid lines) and +-3 sigma limits (dashed lines) for each source for the S1-band observation for the magnetars as well as the ULP ASKAP J1935+2148, which is in the beam of the SGR 1935+2154 observation. The time resolution is 8 s. frequencies due to strongly scattered radio emission. This is due to their tendency of being in more complex structures, where a lot of material is in the lines of … view at source ↗
Figure 4
Figure 4. Figure 4: Overview of the different flux density limits obtained for the sources. Here, we are displaying the limits for 1RXS J170849 at L-band but the other sources and bands are analogue. The solid lines correspond to the limits on the pulsed (pulsar-like) emission from imaging (FIM/X, where X is the duty cycle) and beamforming (S mean) as a function of duty cycle (linear scale). The dashed lines show the limits f… view at source ↗
read the original abstract

Magnetars occupy the neutron star population, with magnetic field strengths of more than 10e12 G. They have been proposed as one of the most likely progenitor models for the phenomenon of energetic, ms-duration, extragalactic radio bursts (FRBs) intensively since FRB-like bursts emitted from the galactic Magnetar SGR 1935+2154. Only a low fraction of the magnetars (six in total) has been detected in the radio regime and most magnetars are radio quiet. We conducted regular observations of 13 radio quiet magnetars to probe the long term radio quietness using MeerKAT. These provide deep constraints on the radio emission of magnetars, relevant for the progenitor models of FRBs Given that MeerKAT is an interferometer, we probe the magnetars for radio emission in both imaging and time domain. We search in the time domain in a DM range of 20 pc/cm^3 to 10000 pc/cm^3 for single pulses using a TransientX based search pipeline (FRB perspective) as well as from a pulsar perspective by folding the data using the X-ray ephemeris. We use the imaging domain to search for radio emission in Stokes I and V as well as to create light curves using snapshot imaging having the long transient perspective as well. We find no radio emission in the time domain for any of the observed magnetars but provide deep limits of the mean flux density 60 uJy and the single pulse fluence of 39 mJy. From the image domain, we provide upper limits on the persistent radio radio emission and the light curve for the 13 magnetars. Additionally, an ULPT and an additional magnetar were observed in the images. We provide an extensive series of deep upper limits in the time domain but also as a novelty limits from the imaging domain for the magnetars. We encourage monitoring of radio quiet magnetars independent of their X-ray flux with high cadence for further insights in their potential for emitting in the radio regime.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 4 minor

Summary. The paper reports MeerKAT observations of 13 radio-quiet magnetars, using both time-domain searches (single-pulse detection over DM 20–10000 pc cm^{-3} via TransientX and folding with X-ray ephemerides) and imaging-domain analysis in Stokes I and V. No radio emission is detected in any target, yielding upper limits of 60 μJy on mean flux density and 39 mJy on single-pulse fluence, plus constraints on persistent emission and light curves; an additional ULPT and magnetar are noted in the images.

Significance. The non-detections and quantitative limits, if robust, tighten constraints on radio emission from magnetars and their viability as FRB progenitors by providing deep, long-term bounds independent of X-ray activity. The dual time- and image-domain approach and use of MeerKAT sensitivity represent a clear empirical contribution.

minor comments (4)
  1. Abstract: the phrase 'persistent radio radio emission' contains a duplicated word; correct to 'persistent radio emission'.
  2. Abstract and §3: the acronym 'ULPT' is introduced without expansion; define it on first use (e.g., 'ultra-long-period transient').
  3. Methods: the exact criteria for excluding RFI or setting the DM search bounds (20–10000 pc cm^{-3}) should be stated more explicitly, including any sensitivity to the assumed range.
  4. Figure captions and text: ensure all flux-density and fluence limits are uniformly quoted with units and reference the relevant observation epochs or integration times.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for their positive assessment of our work and for recommending minor revision. We appreciate the recognition that our non-detections provide robust, long-term constraints on radio emission from radio-quiet magnetars and that the dual time- and image-domain analysis with MeerKAT represents a clear empirical contribution. Since the report does not raise any specific major comments, we will incorporate any minor suggestions during revision.

Circularity Check

0 steps flagged

No significant circularity in direct observational upper limits

full rationale

This is an observational astronomy paper reporting non-detections and quantitative upper limits (mean flux density 60 µJy, single-pulse fluence 39 mJy, plus imaging-domain persistent limits) from MeerKAT data on 13 magnetars. The search uses standard DM range (20–10000 pc cm^{-3}) and X-ray ephemerides for folding; these are external assumptions, not derived internally. No equations, fitted parameters renamed as predictions, self-citation chains, or ansatzes appear in the reported procedure. Results follow directly from telescope sensitivity and dual time-domain/imaging pipelines. The derivation chain is self-contained against external benchmarks with no reduction to inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard assumptions about radio-wave propagation through the interstellar medium and the accuracy of external X-ray timing solutions; no free parameters are fitted to the radio data itself.

axioms (2)
  • domain assumption Dispersion measure range 20–10000 pc cm^{-3} is sufficient to capture any pulsed emission from the targets.
    Stated explicitly in the time-domain search description.
  • domain assumption X-ray ephemerides provide accurate rotational phases for folding radio data.
    Used for the pulsar-perspective search.

pith-pipeline@v0.9.0 · 5917 in / 1345 out tokens · 59530 ms · 2026-05-18T16:07:06.965141+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

91 extracted references · 91 canonical work pages

  1. [1]

    G., Barres de Almeida, U., et al

    Aharonian, F., Akhperjanian, A. G., Barres de Almeida, U., et al. 2008, A&A, 486, 829

    work page 2008

  2. [2]

    & Archibald, R

    An, H. & Archibald, R. 2019, ApJ, 877, L10

    work page 2019

  3. [3]

    Anderson, P. W. & Itoh, N. 1975, Nature, 256, 25

    work page 1975

  4. [4]

    F., Scholz, P., Kaspi, V

    Archibald, R. F., Scholz, P., Kaspi, V . M., Tendulkar, S. P., & Beardmore, A. P. 2020, ApJ, 889, 160

    work page 2020

  5. [5]

    2025, ApJ, 979, 122

    Bai, J., Wang, N., Dai, S., et al. 2025, ApJ, 979, 122

    work page 2025

  6. [6]

    D., Sakamoto, T., Baumgartner, W

    Barthelmy, S. D., Sakamoto, T., Baumgartner, W. H., et al. 2010, GRB Coordi- nates Network, 10528, 1

    work page 2010

  7. [7]

    L., Herrmann, W., & Spitler, L

    Bause, M. L., Herrmann, W., & Spitler, L. G. 2024, A&A, 686, A144

    work page 2024

  8. [8]

    Beloborodov, A. M. 2009, ApJ, 703, 1044

    work page 2009

  9. [9]

    D., Ravi, V ., Belov, K

    Bochenek, C. D., Ravi, V ., Belov, K. V ., et al. 2020, Nature, 587, 59

    work page 2020

  10. [10]

    2019, MNRAS, 484, 2931

    Borghese, A., Rea, N., Turolla, R., et al. 2019, MNRAS, 484, 2931

    work page 2019

  11. [11]

    L., et al

    Burgay, M., Rea, N., Israel, G. L., et al. 2006, 372, 410

    work page 2006

  12. [12]

    L., et al

    Caleb, M., Lenc, E., Kaplan, D. L., et al. 2024, Nature Astronomy, 8, 1159

    work page 2024

  13. [13]

    2022, MNRAS, 510, 1996

    Caleb, M., Rajwade, K., Desvignes, G., et al. 2022, MNRAS, 510, 1996

    work page 2022

  14. [14]

    M., Chatterjee, S., Johnston, S., & Demorest, P

    Camilo, F., Ransom, S. M., Chatterjee, S., Johnston, S., & Demorest, P. 2012, ApJ, 746, 63

    work page 2012

  15. [15]

    M., Halpern, J

    Camilo, F., Ransom, S. M., Halpern, J. P., et al. 2016, 820, 110

    work page 2016

  16. [16]

    M., Halpern, J

    Camilo, F., Ransom, S. M., Halpern, J. P., & Reynolds, J. 2007, ApJ, 666, L93

    work page 2007

  17. [17]

    & Reynolds, J

    Camilo, F. & Reynolds, J. 2007, The Astronomer’s Telegram, 1056, 1

    work page 2007

  18. [18]

    & Ruderman, M

    Chen, K. & Ruderman, M. 1993, ApJ, 402, 264 CHIME/FRB Collaboration, Andersen, B. C., Bandura, K. M., et al. 2020, Na- ture, 587, 54

    work page 1993

  19. [19]

    Cooper, A. J. & Wadiasingh, Z. 2024, MNRAS, 533, 2133

    work page 2024

  20. [20]

    Crawford, F., Hessels, J. W. T., & Kaspi, V . M. 2007, 662, 1183, ADS Bibcode: 2007ApJ...662.1183C

    work page 2007

  21. [21]

    R., Burrows, D., Campana, S., et al

    Cummings, J. R., Burrows, D., Campana, S., et al. 2011, The Astronomer’s Tele- gram, 3488, 1 D’Elia, V ., Barthelmy, S. D., Baumgartner, W. H., et al. 2011, GRB Coordinates Network, 12253, 1

    work page 2011

  22. [22]

    & Kaspi, V

    Dib, R. & Kaspi, V . M. 2014, ApJ, 784, 37

    work page 2014

  23. [23]

    Duncan, R. C. & Thompson, C. 1992, ApJ, 392, L9

    work page 1992

  24. [24]

    & van Kerkwijk, M

    Durant, M. & van Kerkwijk, M. H. 2006, ApJ, 648, 534

    work page 2006

  25. [25]

    L., Turolla, R., et al

    Esposito, P., Israel, G. L., Turolla, R., et al. 2011, MNRAS, 416, 205

    work page 2011

  26. [26]

    2009, ApJ, 690, L105

    Esposito, P., Tiengo, A., Mereghetti, S., et al. 2009, ApJ, 690, L105

    work page 2009

  27. [27]

    Gaensler, B. M. 2014, GRB Coordinates Network, 16533, 1 5 https://www.mpifr-bonn.mpg.de/mmgps Article number, page 9 of 13 A&A proofs:manuscript no. magnetar_search_paper

    work page 2014

  28. [28]

    P., Kaspi, V

    Gavriil, F. P., Kaspi, V . M., & Woods, P. M. 2002, Nature, 419, 142

    work page 2002

  29. [29]

    Gelbord, J. M. & Vetere, L. 2010, GRB Coordinates Network, 10531, 1

    work page 2010

  30. [30]

    & Kouveliotou, C

    Gogus, E. & Kouveliotou, C. 2011, The Astronomer’s Telegram, 3542, 1

    work page 2011

  31. [31]

    2011, The As- tronomer’s Telegram, 3576, 1

    Gogus, E., Kouveliotou, C., Kargaltsev, O., & Pavlov, G. 2011, The As- tronomer’s Telegram, 3576, 1

    work page 2011

  32. [32]

    2010, GRB Coordinates Network, 10534, 1 Göˇgü¸ S , E., Woods, P

    Gogus, E., Strohmayer, T., Kouveliotou, C., & Woods, P. 2010, GRB Coordinates Network, 10534, 1 Göˇgü¸ S , E., Woods, P. M., Kouveliotou, C., et al. 1999, ApJ, 526, L93

    work page 2010

  33. [33]

    Guiriec, S., Kouveliotou, C., & van der Horst, A. J. 2011, GRB Coordinates Network, 12255, 1

    work page 2011

  34. [34]

    P., Gotthelf, E

    Halpern, J. P., Gotthelf, E. V ., Becker, R. H., Helfand, D. J., & White, R. L. 2005, ApJ, 632, L29

    work page 2005

  35. [35]

    2020, oxkat: Semi-automated imaging of MeerKAT observations, Astrophysics Source Code Library, record ascl:2009.003

    Heywood, I. 2020, oxkat: Semi-automated imaging of MeerKAT observations, Astrophysics Source Code Library, record ascl:2009.003

    work page 2020

  36. [36]

    E., Smith, D

    Hurley, K., Boggs, S. E., Smith, D. M., et al. 2005, Nature, 434, 1098

    work page 2005

  37. [37]

    2020, The Astronomer’s Telegram, 13553, 1

    Karuppusamy, R., Desvignes, G., Kramer, M., et al. 2020, The Astronomer’s Telegram, 13553, 1

    work page 2020

  38. [38]

    Kaspi, V . M. & Beloborodov, A. M. 2017, ARA&A, 55, 261

    work page 2017

  39. [39]

    P., Jenkins, M., et al

    Kirsten, F., Snelders, M. P., Jenkins, M., et al. 2021, Nature Astronomy, 5, 414

    work page 2021

  40. [40]

    1999, ApJ, 510, L115

    Kouveliotou, C., Strohmayer, T., Hurley, K., et al. 1999, ApJ, 510, L115

    work page 1999

  41. [41]

    V ., Israel, G

    Kozlova, A. V ., Israel, G. L., Svinkin, D. S., et al. 2016, MNRAS, 460, 2008

    work page 2016

  42. [42]

    G., Fenimore, E

    Laros, J. G., Fenimore, E. E., Klebesadel, R. W., et al. 1987, ApJ, 320, L111

    work page 1987

  43. [43]

    M., Champion, D

    Lazarus, P., Kaspi, V . M., Champion, D. J., Hessels, J. W. T., & Dib, R. 2012, 744, 97, ADS Bibcode: 2012ApJ...744...97L

    work page 2012

  44. [44]

    2010, ApJ, 721, L33

    Levin, L., Bailes, M., Bates, S., et al. 2010, ApJ, 721, L33

    work page 2010

  45. [45]

    G., Desvignes, G., et al

    Levin, L., Lyne, A. G., Desvignes, G., et al. 2019, MNRAS, 488, 5251

    work page 2019

  46. [46]

    Y ., Barthelmy, S

    Lien, A. Y ., Barthelmy, S. D., Baumgartner, W. H., et al. 2014, GRB Coordinates Network, 16522, 1

    work page 2014

  47. [47]

    2022, PASP, 134, 094106

    Lin, H.-H., Lin, K.-y., Li, C.-T., et al. 2022, PASP, 134, 094106

    work page 2022

  48. [48]

    Lorimer, D. R. & Xilouris, K. M. 2000, 545, 385, ADS Bibcode: 2000ApJ...545..385L

    work page 2000

  49. [49]

    E., Younes, G., Scholz, P., et al

    Lower, M. E., Younes, G., Scholz, P., et al. 2023, ApJ, 945, 153

    work page 2023

  50. [50]

    2024, ApJ, 963, 151

    Lu, W.-J., Zhou, P., Wang, P., et al. 2024, ApJ, 963, 151

    work page 2024

  51. [51]

    P., Chandra Joshi, B., & Bagchi, M

    Maan, Y ., Surnis, M. P., Chandra Joshi, B., & Bagchi, M. 2022, ApJ, 931, 67

    work page 2022

  52. [52]

    P., Golenetskii, S

    Mazets, E. P., Golenetskii, S. V ., Ilinskii, V . N., et al. 1981, Ap&SS, 80, 3

    work page 1981

  53. [53]

    P., Golenetskij, S

    Mazets, E. P., Golenetskij, S. V ., & Guryan, Y . A. 1979, Soviet Astronomy Let- ters, 5, 343

    work page 1979

  54. [54]

    & Barr, E

    Men, Y . & Barr, E. 2024, A&A, 683, A183

    work page 2024

  55. [55]

    J., Carli, E., & Desvignes, G

    Men, Y ., Barr, E., Clark, C. J., Carli, E., & Desvignes, G. 2023, A&A, 679, A20

    work page 2023

  56. [56]

    D., Stappers, B

    Morello, V ., Barr, E. D., Stappers, B. W., Keane, E. F., & Lyne, A. G. 2020, MNRAS, 497, 4654

    work page 2020

  57. [57]

    P., Clark, J

    Muno, M. P., Clark, J. S., Crowther, P. A., et al. 2006, ApJ, 636, L41

    work page 2006

  58. [58]

    L., et al

    Murphy, T., Chatterjee, S., Kaplan, D. L., et al. 2013, PASA, 30, e006

    work page 2013

  59. [59]

    Olausen, S. A. & Kaspi, V . M. 2014, ApJS, 212, 6

    work page 2014

  60. [60]

    V ., Barr, E

    Padmanabh, P. V ., Barr, E. D., Sridhar, S. S., et al. 2023, MNRAS, 524, 1291

    work page 2023

  61. [61]

    & Kramer, M

    Philippov, A. & Kramer, M. 2022, ARA&A, 60, 495

    work page 2022

  62. [62]

    Ransom, S. M. 2001, PhD thesis, Harvard University, Massachusetts

    work page 2001

  63. [63]

    L., Pons, J

    Rea, N., Viganò, D., Israel, G. L., Pons, J. A., & Torres, D. F. 2014, ApJ, 781, L17

    work page 2014

  64. [64]

    F., Kaspi, V

    Scholz, P., Archibald, R. F., Kaspi, V . M., et al. 2014, ApJ, 783, 99

    work page 2014

  65. [65]

    D., Charles, P

    Seward, F. D., Charles, P. A., & Smale, A. P. 1986, ApJ, 305, 814

    work page 1986

  66. [66]

    Shannon, R. M. & Johnston, S. 2013, MNRAS, 435, L29

    work page 2013

  67. [67]

    G., Cordes, J

    Spitler, L. G., Cordes, J. M., Chatterjee, S., & Stone, J. 2012, ApJ, 748, 73

    work page 2012

  68. [68]

    L., & Sakamoto, T

    Stamatikos, M., Malesani, D., Page, K. L., & Sakamoto, T. 2014, GRB Coordi- nates Network, 16520, 1

    work page 2014

  69. [69]

    1997, PASJ, 49, L25

    Sugizaki, M., Nagase, F., Torii, K., et al. 1997, PASJ, 49, L25

    work page 1997

  70. [70]

    I., & Gil, J

    Szary, A., Melikidze, G. I., & Gil, J. 2015, ApJ, 800, 76

    work page 2015

  71. [71]

    Tauris, T. M. & Manchester, R. N. 1998, MNRAS, 298, 625

    work page 1998

  72. [72]

    P., Hummel, W., Rea, N., & Israel, G

    Testa, V ., Mignani, R. P., Hummel, W., Rea, N., & Israel, G. L. 2018, MNRAS, 473, 3180

    work page 2018

  73. [73]

    & Duncan, R

    Thompson, C. & Duncan, R. C. 1993, ApJ, 408, 194

    work page 1993

  74. [74]

    2019, in Canadian Long Range Plan for Astronomy and Astrophysics White Papers, V ol

    Vanderlinde, K., Liu, A., Gaensler, B., et al. 2019, in Canadian Long Range Plan for Astronomy and Astrophysics White Papers, V ol. 2020, 28

    work page 2019

  75. [75]

    & Gotthelf, E

    Vasisht, G. & Gotthelf, E. V . 1997, ApJ, 486, L129

    work page 1997

  76. [76]

    R., Frail, D

    Vasisht, G., Kulkarni, S. R., Frail, D. A., & Greiner, J. 1994, ApJ, 431, L35 V oges, W., Aschenbach, B., Boller, T., et al. 1999, A&A, 349, 389

    work page 1994

  77. [77]

    K., Kouveliotou, C., et al

    Wachter, S., Patel, S. K., Kouveliotou, C., et al. 2004, ApJ, 615, 887

    work page 2004

  78. [78]

    2024, ApJS, 275, 39

    Wang, P., Li, J., Ji, L., et al. 2024, ApJS, 275, 39

    work page 2024

  79. [79]

    2019, ApJ, 875, 84

    Wang, W., Zhang, B., Chen, X., & Xu, R. 2019, ApJ, 875, 84

    work page 2019

  80. [80]

    & Chakrabarty, D

    Wang, Z. & Chakrabarty, D. 2002, ApJ, 579, L33

    work page 2002

Showing first 80 references.