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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"

342 results found.

  1. GRB 250507A: refined SVOM/MXT data analysis
  2. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  3. GRB 250331C: Swift/UVOT Upper Limits
  4. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  5. IceCube-250309A: Upper limits from a search for additional neutrino events in IceCube
  6. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  7. IceCube-Cascade 250215A: Upper limits from a search for additional neutrino events in IceCube
  8. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  9. IceCube-250102A: Upper limits from a search for additional neutrino events in IceCube
  10. Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
  11. GRB 241130A: EIRSAT-1 GMOD Detection
  12. IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
  13. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  14. EP241113a: Swift XRT weak detection
  15. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  16. SVOM/GRM detection of a short burst from SGR 1E1841-045
  17. INTEGRAL detection of a burst from 1E 1841-045
  18. EP241107a: EP on-board trigger and autonomous follow-up observation
  19. EP241025a (GRB 241025A): EP observations update
  20. GRB241017A: TOO Observations by SVOM/MXT
  21. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  22. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  23. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  24. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  25. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  26. GRB 240824A: Swift/UVOT Upper Limits
  27. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  28. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  29. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  30. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  31. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  32. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  33. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  34. GRB 240802A: AstroSat CZTI detection of a long burst
  35. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  36. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  37. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  39. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  41. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  43. GRB 240106A: Glowbug gamma-ray detection
  44. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  45. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  46. GRB 231204A: AstroSat CZTI detection
  47. GRB 231123A: AstroSat CZTI detection
  48. Fermi GRB 231108A: Global MASTER-Net observations report
  49. LIGO/Virgo/KAGRA S231014r: Identification of a GW compact binary merger candidate
  50. GRB 230824A: AKO Photometric Follow-up Observations
  51. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  52. IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
  53. IceCube-230725A: Upper limits from a search for additional neutrino events in IceCube
  54. GRB 230723B: Optical afterglow candidate from CAHA
  55. IceCube-230708A: Upper limits from a search for additional neutrino events in IceCube
  56. IceCube-230707B: Upper limits from a search for additional neutrino events in IceCube
  57. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  58. IceCube-Cascade 230610A: Upper limits from a search for additional neutrino events in IceCube
  59. LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  61. LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
  62. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  63. IceCube-Cascade 230511A: Upper limits from a search for additional neutrino events in IceCube
  64. IceCube-Cascade 230430A: Upper limits from a search for additional neutrino events in IceCube
  65. IceCube-230416A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  67. INTEGRAL detection of a burst from SGR 1806-200
  68. GRB 230307A: soft X-ray detection with LEIA
  69. GRB 230307A: GECAM detection of an extremely bright burst
  70. IceCube-230220A: Upper limits from a search for additional neutrino events in IceCube
  71. IceCube-230201A: Upper limits from a search for additional neutrino events in IceCube
  72. IceCube-230122A: Upper limits from a search for additional neutrino events in IceCube
  73. Fermi-LAT gamma-ray observations of IceCube-230112A
  74. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  75. Fermi-LAT gamma-ray observations of IceCube-221223A
  76. IceCube-221216A: Upper limits from a search for additional neutrino events in IceCube
  77. IceCube-221124A: Upper limits from a search for additional neutrino events in IceCube
  78. IceCube-221104A: Upper limits from a search for additional neutrino events in IceCube
  79. Konus-Wind observation of the recent SGR 1935+2154 activity
  80. INTEGRAL detection of a burst from SGR J1935+2154
  81. IceCube-220928A: Upper limits from a search for additional neutrino events in IceCube
  82. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  83. IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
  84. IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
  85. IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
  86. GRB 220518A: Swift/UVOT Detection
  87. IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube-220425A: Upper limits from a search for additional neutrino events in IceCube
  89. IceCube-220424A: Upper limits from a search for additional neutrino events in IceCube
  90. IceCube-220421A: Upper limits from a search for additional neutrino events in IceCube
  91. IceCube-220317A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-220306A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-220303A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB 220228A: Fermi-LAT detection
  95. GRB 220101A: The first example of a Petanova
  96. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  97. IceCube-211216A: Upper limits from a search for additional neutrino events in IceCube
  98. IceCube-211216A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  99. IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube
  100. IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation

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