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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"

27784 results found.

  1. EP241201a: BOOTES-5 optical upper limit
  2. EP241202b: EP detection of a fast X-ray transient
  3. IPN triangulation of GRB 241130A
  4. GRB 241130A: EIRSAT-1 GMOD Detection
  5. GRB 241128A: Swift/UVOT Upper Limits
  6. GRB 241130A: Fermi GBM Detection
  7. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  8. EP241201a: Kinder optical counterpart candidate
  9. EP241201a: EP detection of a fast X-ray transient
  10. GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
  11. GRB241201B: Fermi GBM Final Localization
  12. GRB241201B: Fermi GBM Final Localization
  13. GRB 241130A: Fermi GBM Final Real-time Localization
  14. GRB 241130A: Fermi GBM Final Real-time Localization
  15. GRB 241201A: Fermi GBM Final Real-time Localization
  16. IPN triangulation of GRB 241128B
  17. Konus-Wind detection of GRB 241114B
  18. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  19. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  20. GRB 241128A: Swift-BAT refined analysis
  21. GRB 241127A: Swift-BAT refined analysis
  22. GRB 241127A: PRIME near-infrared detection
  23. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  24. Swift-XRT observations of IceCube -241127A
  25. Swift GRB 241128A: Global MASTER-Net observations report
  26. GRB 241128A: Swift-XRT refined Analysis
  27. GRB 241129A: Fermi GBM Final Real-time Localization
  28. GRB 241128A: Enhanced Swift-XRT position
  29. GRB 241128A: LCO optical detection
  30. GRB 241128A: 1.5m OSN optical afterglow detection
  31. GRB 241128A: Swift-XRT afterglow detection
  32. GRB 241128A: Swift detection of a burst
  33. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  34. GRB 241127A: Swift/UVOT Detection
  35. GRB 241127A: Swift-XRT refined Analysis
  36. GRB 241127A: SVOM/GRM observation
  37. GRB 241127A: Enhanced Swift-XRT position
  38. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  39. Swift GRB241127.91: Global MASTER-Net OT detection
  40. EP241126a: WFST Observations
  41. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  42. GRB 241127A: Swift detection of a burst with an optical counterpart
  43. Swift GRB241127.91: Global MASTER-Net observations report
  44. Swift GRB241127.91: Global MASTER-Net OT detection
  45. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  46. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  47. IceCube-241127A: IceCube observation of a high-energy neutrino candidate track-like event
  48. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  49. EP241126a: Optical Upper limits with Kinder observations
  50. IPN triangulation of GRB 241114B
  51. EP241126a: EP-FXT follow-up observation update
  52. EP241126a: GSP detects optical counterpart
  53. EP241126a: TRT optical counterpart detection
  54. EP241126a: EP detection of a fast X-ray transient
  55. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
  56. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  57. Trigger_18947: Swift ToO observations (retracted)
  58. GRB 241113B: EP-FXT afterglow detection
  59. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  60. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  61. SVOM/GRM detection of a short burst from SGR 1830
  62. GECAM detection of a short burst from SGR 1830
  63. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  64. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  65. Konus-Wind detection of GRB 241115D / EP 241115a
  66. GRB 241026A: radio detection with the VLA
  67. EP241125a: EP detection of an X-ray transient
  68. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  69. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  70. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  71. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  72. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  73. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  74. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  75. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  76. GRB 241120A: GRBAlpha detection
  77. Konus-Wind detection of GRB 241117A
  78. GRB 241105A: ATCA radio detection
  79. IPN triangulation of GRB 241117A
  80. GRB 241026A: VIRT Optical Upper Limit
  81. GRB 241025A: VIRT Optical Upper Limit
  82. Konus-Wind detection of GRB 241120A
  83. GRB241120A: OHP/T193 optical observations
  84. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  85. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  86. GRB 241113A: Possible ATCA Radio detection
  87. GRB 241114B: Insight-HXMT/HE detection
  88. EP241119a: EP detection of a fast X-ray transient
  89. GRB 241120A: Fermi GBM Final Real-time Localization
  90. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  91. GRB 241119A: Fermi GBM Final Real-time Localization
  92. GRB 241115a: PRIME near-infrared upper limits
  93. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  94. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  95. GRB 241115B: Fermi GBM Observation
  96. GRB 241118A: Fermi GBM Final Real-time Localization
  97. GRB 241117A: Fermi GBM Detection
  98. GRB 241117B: Fermi GBM Final Real-time Localization
  99. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  100. GRB 241117A: Fermi GBM Final Real-time Localization

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