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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. GRB 241204A: DDOTI Upper Limits on the Afterglow
  2. GRB 241204A: Fermi GBM Observation
  3. Fermi GRB 241204A: Global MASTER-Net observations report
  4. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  5. GRB 241128A : RAPAS follow-up observations
  6. GRB 241201A: GRBAlpha detection
  7. GRB 241204A: Fermi-LAT detection
  8. EP241202b: Upper limits from Fermi-GBM Observations
  9. IceCube-241127A: No transient candidates from the Zwicky Transient Facility
  10. EP241202b: Kinder optical counterpart candidate
  11. Fermi-GBM Sub-Threshold Detection of GRB 241128A
  12. GRB 241113B : RAPAS follow-up observation
  13. EP241201a: EP-FXT follow-up observations
  14. Konus-Wind detection of GRB 241130A
  15. EP241202b: Global MASTER-Net observations report
  16. EP241201a: BOOTES-5 optical upper limit
  17. EP241202b: EP detection of a fast X-ray transient
  18. EP241201a: NOT optical observations
  19. IPN triangulation of GRB 241130A
  20. GRB 241130A: EIRSAT-1 GMOD Detection
  21. GRB 241128A: Swift/UVOT Upper Limits
  22. GRB 241130A: Fermi GBM Detection
  23. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  24. GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
  25. EP241201a: Kinder optical counterpart candidate
  26. LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
  27. EP241201a: Global MASTER-Net observations report
  28. EP241201a: EP detection of a fast X-ray transient
  29. The EP-WXT trigger 01709126243 is not a real source
  30. GRB 241127B: detection of a long GRB by SVOM/ECLAIRs
  31. GRB241201B: Fermi GBM Final Localization
  32. GRB241201B: Fermi GBM Final Localization
  33. LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
  34. EP241126a: SOAR observations of the optical counterpart
  35. Fermi GRB 241201A: Global MASTER-Net observations report
  36. GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
  37. GRB 241130A: Fermi GBM Final Real-time Localization
  38. GRB 241130A: Fermi GBM Final Real-time Localization
  39. EP241126a: 1.6m Mephisto Optical Upper Limits
  40. GRB 241201A: Fermi GBM Final Real-time Localization
  41. LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
  42. LIGO/Virgo/KAGRA S241130be: Updated Sky localization
  43. Fermi trigger No 754701230: Global MASTER-Net observations report
  44. IPN triangulation of GRB 241128B
  45. Konus-Wind detection of GRB 241114B
  46. LIGO/Virgo/KAGRA S241130n: Updated Sky localization
  47. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  48. GRB 241128A: AbAO optical upper limit
  49. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  50. LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
  51. LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
  52. LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
  53. SVOM/GRM observation of a short burst from soft gamma repeater Kes 73
  54. GRB 241128C: SVOM/GRM observation
  55. GRB 241128B: SVOM/GRM observation
  56. GRB 241128A: Swift-BAT refined analysis
  57. GRB 241127A: Swift-BAT refined analysis
  58. EP241126a: NOT optical observations
  59. GRB 241127A: PRIME near-infrared detection
  60. GRB 241128A: Mondy optical observations
  61. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  62. Swift-XRT observations of IceCube -241127A
  63. Swift GRB 241128A: Global MASTER-Net observations report
  64. Fermi-LAT gamma-ray observations of IceCube-241127A
  65. EP241126a: SVOM/VT observations
  66. LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
  67. GRB 241128A: Swift-XRT refined Analysis
  68. GRB 241129A: Fermi GBM Final Real-time Localization
  69. GRB 241128A: Enhanced Swift-XRT position
  70. GRB 241128A: NOT optical observations
  71. GRB 241128A: LCO optical detection
  72. GRB 241128A: 1.5m OSN optical afterglow detection
  73. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  74. Fermi trigger No 754492985: Global MASTER-Net observations report
  75. GRB 241128A: Swift-XRT afterglow detection
  76. GRB 241128A: Swift detection of a burst
  77. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  78. GRB 241127A: Swift/UVOT Detection
  79. GRB 241127A: Swift-XRT refined Analysis
  80. GRB 241127A: SVOM/GRM observation
  81. GRB 241127A: Enhanced Swift-XRT position
  82. LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
  83. The EP-WXT trigger 01709125191 is not a real source
  84. GRB 241127A: LCOGT (40-cm) optical counterpart detection
  85. Swift GRB241127.91: Global MASTER-Net OT detection
  86. EP241126a: WFST Observations
  87. LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
  88. IceCube Alert 241127.59: Global MASTER-Net observations report
  89. GRB 241127A: Swift detection of a burst with an optical counterpart
  90. Swift GRB241127.91: Global MASTER-Net observations report
  91. Swift GRB241127.91: Global MASTER-Net OT detection
  92. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  93. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  94. IceCube-241127A: IceCube observation of a high-energy neutrino candidate track-like event
  95. LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
  96. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345)
  97. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations (duplicate submission of 38345).
  98. LIGO/Virgo/KAGRA S241125n: EP-FXT follow-up observations
  99. EP241126a: Optical Upper limits with Kinder observations
  100. SVOM/GRM observation of GRB 241126B or a short burst from magnetar

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