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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"

11503 results found.

  1. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  2. GRB 241120A: GRBAlpha detection
  3. Konus-Wind detection of GRB 241117A
  4. GRB 241105A: ATCA radio detection
  5. Konus-Wind detection of GRB 241120A
  6. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  7. GRB 241120A: Mondy and AbAO optical observations
  8. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  9. EP241119a: GIT optical upper limits
  10. GRB 241120A: Fermi GBM Observation
  11. Integral GRB241120.25: Global MASTER-Net observations report
  12. EP241119a: Global MASTER-Net observations report
  13. EP241119a: EP detection of a fast X-ray transient
  14. GRB241120A: a long GRB detected by INTEGRAL
  15. GRB 241120A: Fermi GBM Final Real-time Localization
  16. GRB 241119A: Fermi GBM Final Real-time Localization
  17. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  18. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  19. Fermi GRB 241118A: Global MASTER-Net observations report
  20. Fermi GRB 241117B: Global MASTER-Net observations report
  21. GRB 241117B: Fermi GBM Final Real-time Localization
  22. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  23. Fermi GRB 241117A: Global MASTER-Net observations report
  24. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  25. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  26. EP241115a: EP detection of a fast X-ray transient
  27. GRB 241115A: Swift detection of a burst
  28. EP 241113a: LBT possible optical counterpart
  29. GRB 241113B: KAIT Optical Afterglow Candidate
  30. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  31. GRB 241030A: LCO optical observation
  32. EP241113b: Global MASTER-Net observations report
  33. Fermi-LAT gamma-ray observations of IceCube-241113A
  34. GRB 241113A: Swift-XRT refined Analysis
  35. Konus-Wind detection of GRB 241107A (short/hard)
  36. GRB 241112B: GMG Optical Upper Limit
  37. GRB 241113B : detection of a long GRB by SVOM/ECLAIRs
  38. Fermi trigger No 753166198: Global MASTER-Net observations report
  39. GRB 241107A: GROWTH-India telescope optical upper limit
  40. GRB 241112B: Swift-XRT afterglow detection
  41. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  42. GRB 241107A: INTEGRAL IBIS localization
  43. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  44. GRB 241018A: cubesat Avion detection
  45. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  46. Fermi trigger No 752878030: Global MASTER-Net observations report
  47. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  48. INTEGRAL detection of a burst from 1E 1841-045
  49. LIGO/Virgo/KAGRA S241109bn: Global MASTER-Net observations report
  50. EP241109a: confirmation of a stellar flare by BOOTES-7
  51. GRB 241108A : a likely weak long GRB detected by SVOM/ECLAIRs
  52. EP241107a: AKO Optical Afterglow Follow-Up Observations
  53. EP241107a: AKO Optical Afterglow Detection
  54. Konus-Wind detection of GRB 241105A (short with extended emission)
  55. Konus-Wind detection of GRB 241021A
  56. Fermi GRB 241105A: Global MASTER-Net observations report
  57. EP241104a: EP detection of GRB 241104A X-ray emission
  58. Fermi GRB 241104A: Global MASTER-Net observations report
  59. EP241103a: GIT optical upper limit
  60. EP241021a: OHP/T193 further optical observations
  61. Fermi trigger No 752365806: Global MASTER-Net observations report
  62. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  63. EP241101a: OHP/T193 optical observations
  64. EP241103a: EP observation update
  65. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  66. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  67. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  68. EP241103a: Global MASTER-Net observations report
  69. EP241103a: an X-ray transient detected by Einstein Probe
  70. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  71. EP241021a: Upper limit from Konus-Wind observations
  72. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  73. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  74. EP241026b: Liverpool Telescope optical follow-up
  75. Fermi trigger No 752083996: Global MASTER-Net observations report
  76. GRB 241030A: SAO RAS optical observations
  77. GRB 241030A: Fermi GBM Observation
  78. EP241021a: AMI-LA radio detection
  79. GRB 241030B : GIT optical upper limits
  80. EP EP241030a: Global MASTER-Net observations report
  81. Fermi trigger No 752006065: Global MASTER-Net observations report
  82. Swift GRB241030.77: Global MASTER-Net observations report
  83. GRB241030B: Fermi GBM Observation
  84. GRB 241030B: BTA observations
  85. GRB 241030B: optical observations from the INAF Asiago Observatory
  86. GRB 241030B: Nanshan/HMT optical afterglow detection
  87. Konus-Wind detection of GRB 241030A
  88. GRB 241030B: Swift detection of a burst
  89. GRB 241030B: Fermi GBM Final Real-time Localization
  90. GRB 241030A: Fermi-LAT detection
  91. GRB 241030A: Swift/UVOT Detection
  92. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  93. EP241021a: ATCA radio observations
  94. GRB 241029A: Fermi GBM Observation
  95. Fermi trigger No 751861204: Global MASTER-Net observations report
  96. Konus-Wind detection of GRB 241025A
  97. GRB 241025A: further SAO RAS optical observations
  98. GRB 241026A: BTA and Zeiss-1000 optical observations
  99. GRB 241026A Fermi GBM Analysis
  100. GRB 241025A: SAO RAS optical observations

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