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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

45437 results found.

  1. Swift GRB241209.23: Global MASTER-Net observations report
  2. GRB 241209A: Fermi GBM Final Real-time Localization
  3. Fermi GRB 241207B: Global MASTER-Net observations report
  4. GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
  5. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  6. GRB 241201A: AstroSat CZTI detection
  7. GRB 241206A: DDOTI Upper Limit on the Afterglow
  8. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  9. AT2024adec: X-ray Upper Limits from EP-FXT Observation
  10. EP241206a: BOOTES Global Network optical limits
  11. GRB 241207C: MASTER optical observations
  12. Fermi trigger No 755225799: Global MASTER-Net observations report
  13. GRB 241207C: Tiled Swift observations
  14. GRB 241207C: MAXI/GSC detection
  15. GRB 241207B: Fermi GBM Final Real-time Localization
  16. Fermi trigger No 755277791: Global MASTER-Net observations report
  17. Fermi GRB 241207A: Global MASTER-Net observations report
  18. EP241206a: Global MASTER-Net observations report
  19. EP241206a: EP detection of a fast X-ray transient
  20. GRB 241206A: Fermi GBM observation
  21. GRB 241206C: SVOM/GRM observation of a likely short burst
  22. GRB 241207A: Fermi GBM Final Real-time Localization
  23. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  24. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  25. GRB 241206B: GWAC-F50A optical upper limit
  26. GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
  27. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  28. Fermi GRB 241206A: Global MASTER-Net observations report
  29. GRB 241206A: Fermi GBM Final Real-time Localization
  30. EP241201a: 1.6m Mephisto Optical Upper Limits
  31. GRB 241204A: COLIBRÍ Optical Upper Limit
  32. EP241202b: KAIT optical upper limit
  33. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  34. GRB 241204A: DDOTI Upper Limits on the Afterglow
  35. GRB 241204A: Fermi GBM Observation
  36. Fermi GRB 241204A: Global MASTER-Net observations report
  37. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  38. GRB 241128A : RAPAS follow-up observations
  39. GRB 241201A: GRBAlpha detection
  40. GRB 241204A: Fermi-LAT detection
  41. EP241202b: Upper limits from Fermi-GBM Observations
  42. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  43. EP241202b: Kinder optical counterpart candidate
  44. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  45. GRB 241113B : RAPAS follow-up observation
  46. EP241201a: EP-FXT follow-up observations
  47. Konus-Wind detection of GRB 241130A
  48. EP241202b: Global MASTER-Net observations report
  49. EP241201a: BOOTES-5 optical upper limit
  50. EP241202b: EP detection of a fast X-ray transient
  51. EP241201a: NOT optical observations
  52. IPN triangulation of GRB 241130A
  53. GRB 241130A: EIRSAT-1 GMOD Detection
  54. GRB 241128A: Swift/UVOT Upper Limits
  55. GRB 241130A: Fermi GBM Detection
  56. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  57. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  58. EP241201a: Kinder optical counterpart candidate
  59. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  60. EP241201a: Global MASTER-Net observations report
  61. EP241201a: EP detection of a fast X-ray transient
  62. The EP-WXT trigger 01709126243 is not a real source
  63. GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
  64. GRB241201B: Fermi GBM Final Localization
  65. GRB241201B: Fermi GBM Final Localization
  66. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  67. EP241126a: SOAR observations of the optical counterpart
  68. Fermi GRB 241201A: Global MASTER-Net observations report
  69. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  70. GRB 241130A: Fermi GBM Final Real-time Localization
  71. GRB 241130A: Fermi GBM Final Real-time Localization
  72. EP241126a: 1.6m Mephisto Optical Upper Limits
  73. GRB 241201A: Fermi GBM Final Real-time Localization
  74. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  75. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  76. Fermi trigger No 754701230: Global MASTER-Net observations report
  77. IPN triangulation of GRB 241128B
  78. Konus-Wind detection of GRB 241114B
  79. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  80. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  81. GRB 241128A: AbAO optical upper limit
  82. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  83. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  85. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  86. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  87. GRB 241128C: SVOM/GRM observation
  88. GRB 241128B: SVOM/GRM observation
  89. GRB 241128A: Swift-BAT refined analysis
  90. GRB 241127A: Swift-BAT refined analysis
  91. EP241126a: NOT optical observations
  92. GRB 241127A: PRIME near-infrared detection
  93. GRB 241128A: Mondy optical observations
  94. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  95. Swift-XRT observations of IceCube -241127A
  96. Swift GRB 241128A: Global MASTER-Net observations report
  97. Fermi-LAT gamma-ray observations of IceCube-241127A
  98. EP241126a: SVOM/VT observations
  99. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  100. GRB 241128A: Swift-XRT refined Analysis

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