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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').
Advanced Search

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"

39057 results found.

  1. GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
  2. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  3. GRB 241206B: GWAC-F50A optical upper limit
  4. GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
  5. Fermi GRB 241206A: Global MASTER-Net observations report
  6. GRB 241206A: Fermi GBM Final Real-time Localization
  7. EP241201a: 1.6m Mephisto Optical Upper Limits
  8. GRB 241204A: COLIBRÍ Optical Upper Limit
  9. EP241202b: KAIT optical upper limit
  10. LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  11. GRB 241204A: DDOTI Upper Limits on the Afterglow
  12. GRB 241204A: Fermi GBM Observation
  13. Fermi GRB 241204A: Global MASTER-Net observations report
  14. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  15. GRB 241128A : RAPAS follow-up observations
  16. GRB 241201A: GRBAlpha detection
  17. GRB 241204A: Fermi-LAT detection
  18. EP241202b: Upper limits from Fermi-GBM Observations
  19. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  20. GRB 241113B : RAPAS follow-up observation
  21. Konus-Wind detection of GRB 241130A
  22. EP241202b: Global MASTER-Net observations report
  23. IPN triangulation of GRB 241130A
  24. GRB 241130A: EIRSAT-1 GMOD Detection
  25. GRB 241128A: Swift/UVOT Upper Limits
  26. GRB 241130A: Fermi GBM Detection
  27. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  28. EP241201a: Kinder optical counterpart candidate
  29. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  30. EP241201a: Global MASTER-Net observations report
  31. GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
  32. GRB241201B: Fermi GBM Final Localization
  33. GRB241201B: Fermi GBM Final Localization
  34. Fermi GRB 241201A: Global MASTER-Net observations report
  35. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  36. GRB 241130A: Fermi GBM Final Real-time Localization
  37. GRB 241130A: Fermi GBM Final Real-time Localization
  38. EP241126a: 1.6m Mephisto Optical Upper Limits
  39. GRB 241201A: Fermi GBM Final Real-time Localization
  40. Fermi trigger No 754701230: Global MASTER-Net observations report
  41. IPN triangulation of GRB 241128B
  42. Konus-Wind detection of GRB 241114B
  43. GRB 241128A: AbAO optical upper limit
  44. GRB 241128C: SVOM/GRM observation
  45. GRB 241128B: SVOM/GRM observation
  46. GRB 241128A: Swift-BAT refined analysis
  47. GRB 241127A: Swift-BAT refined analysis
  48. GRB 241127A: PRIME near-infrared detection
  49. GRB 241128A: Mondy optical observations
  50. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  51. Swift GRB 241128A: Global MASTER-Net observations report
  52. GRB 241128A: Swift-XRT refined Analysis
  53. GRB 241129A: Fermi GBM Final Real-time Localization
  54. GRB 241128A: Enhanced Swift-XRT position
  55. GRB 241128A: NOT optical observations
  56. GRB 241128A: LCO optical detection
  57. GRB 241128A: 1.5m OSN optical afterglow detection
  58. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  59. Fermi trigger No 754492985: Global MASTER-Net observations report
  60. GRB 241128A: Swift-XRT afterglow detection
  61. GRB 241128A: Swift detection of a burst
  62. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  63. GRB 241127A: Swift/UVOT Detection
  64. GRB 241127A: Swift-XRT refined Analysis
  65. GRB 241127A: SVOM/GRM observation
  66. GRB 241127A: Enhanced Swift-XRT position
  67. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  68. Swift GRB241127.91: Global MASTER-Net OT detection
  69. IceCube Alert 241127.59: Global MASTER-Net observations report
  70. GRB 241127A: Swift detection of a burst with an optical counterpart
  71. Swift GRB241127.91: Global MASTER-Net observations report
  72. Swift GRB241127.91: Global MASTER-Net OT detection
  73. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  74. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  75. SVOM/GRM observation of GRB 241126B or a short burst from magnetar
  76. GRB 241126A: SVOM/GRM observation
  77. IPN triangulation of GRB 241114B
  78. EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
  79. EP241126a: GSP detects optical counterpart
  80. EP241126a: TRT optical counterpart detection
  81. GRB 241113B: EP-FXT afterglow detection
  82. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  83. SVOM/GRM detection of a short burst from SGR 1830
  84. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  85. Konus-Wind detection of GRB 241115D / EP 241115a
  86. LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
  87. GRB 241026A: radio detection with the VLA
  88. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  89. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  90. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  91. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  92. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  93. GRB 241120A: GRBAlpha detection
  94. GRB 241113B: SVOM/VT optical afterglow observations
  95. Konus-Wind detection of GRB 241117A
  96. GRB 241105A: ATCA radio detection
  97. IPN triangulation of GRB 241117A
  98. GRB 241026A: VIRT Optical Upper Limit
  99. GRB 241025A: VIRT Optical Upper Limit
  100. Konus-Wind detection of GRB 241120A

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