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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"

27774 results found.

  1. GRB241201B: Fermi GBM Final Localization
  2. GRB241201B: Fermi GBM Final Localization
  3. GRB 241130A: Fermi GBM Final Real-time Localization
  4. GRB 241130A: Fermi GBM Final Real-time Localization
  5. GRB 241201A: Fermi GBM Final Real-time Localization
  6. IPN triangulation of GRB 241128B
  7. Konus-Wind detection of GRB 241114B
  8. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  9. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  10. GRB 241128A: Swift-BAT refined analysis
  11. GRB 241127A: Swift-BAT refined analysis
  12. GRB 241127A: PRIME near-infrared detection
  13. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  14. Swift-XRT observations of IceCube -241127A
  15. Swift GRB 241128A: Global MASTER-Net observations report
  16. GRB 241128A: Swift-XRT refined Analysis
  17. GRB 241129A: Fermi GBM Final Real-time Localization
  18. GRB 241128A: Enhanced Swift-XRT position
  19. GRB 241128A: LCO optical detection
  20. GRB 241128A: 1.5m OSN optical afterglow detection
  21. GRB 241128A: Swift-XRT afterglow detection
  22. GRB 241128A: Swift detection of a burst
  23. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  24. GRB 241127A: Swift/UVOT Detection
  25. GRB 241127A: Swift-XRT refined Analysis
  26. GRB 241127A: SVOM/GRM observation
  27. GRB 241127A: Enhanced Swift-XRT position
  28. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  29. Swift GRB241127.91: Global MASTER-Net OT detection
  30. EP241126a: WFST Observations
  31. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  32. GRB 241127A: Swift detection of a burst with an optical counterpart
  33. Swift GRB241127.91: Global MASTER-Net observations report
  34. Swift GRB241127.91: Global MASTER-Net OT detection
  35. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  36. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  37. IceCube-241127A: IceCube observation of a high-energy neutrino candidate track-like event
  38. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  39. EP241126a: Optical Upper limits with Kinder observations
  40. IPN triangulation of GRB 241114B
  41. EP241126a: EP-FXT follow-up observation update
  42. EP241126a: GSP detects optical counterpart
  43. EP241126a: TRT optical counterpart detection
  44. EP241126a: EP detection of a fast X-ray transient
  45. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  46. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  47. Trigger_18947: Swift ToO observations (retracted)
  48. GRB 241113B: EP-FXT afterglow detection
  49. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  50. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  51. SVOM/GRM detection of a short burst from SGR 1830
  52. GECAM detection of a short burst from SGR 1830
  53. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  54. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  55. Konus-Wind detection of GRB 241115D / EP 241115a
  56. GRB 241026A: radio detection with the VLA
  57. EP241125a: EP detection of an X-ray transient
  58. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  59. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  60. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  61. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  62. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  63. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  64. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  65. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  66. GRB 241120A: GRBAlpha detection
  67. Konus-Wind detection of GRB 241117A
  68. GRB 241105A: ATCA radio detection
  69. IPN triangulation of GRB 241117A
  70. GRB 241026A: VIRT Optical Upper Limit
  71. GRB 241025A: VIRT Optical Upper Limit
  72. Konus-Wind detection of GRB 241120A
  73. GRB241120A: OHP/T193 optical observations
  74. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  75. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  76. GRB 241113A: Possible ATCA Radio detection
  77. GRB 241114B: Insight-HXMT/HE detection
  78. EP241119a: EP detection of a fast X-ray transient
  79. GRB 241120A: Fermi GBM Final Real-time Localization
  80. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  81. GRB 241119A: Fermi GBM Final Real-time Localization
  82. GRB 241115a: PRIME near-infrared upper limits
  83. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  84. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  85. GRB 241115B: Fermi GBM Observation
  86. GRB 241118A: Fermi GBM Final Real-time Localization
  87. GRB 241117A: Fermi GBM Detection
  88. GRB 241117B: Fermi GBM Final Real-time Localization
  89. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  90. GRB 241117A: Fermi GBM Final Real-time Localization
  91. GRB 241115C: Fermi GBM Observation
  92. GRB 241115A: Swift-XRT afterglow detection
  93. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  94. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  95. EP241113a: Swift XRT weak detection
  96. GRB 241115A: Fermi GBM Observation
  97. GRB 241115A: LCOGT Optical Upper Limits
  98. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  99. GRB 241115B: Fermi GBM Final Real-time Localization
  100. EP241115a: EP detection of a fast X-ray transient

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