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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"

11752 results found.

  1. EP241107a: AKO Optical Afterglow Follow-Up Observations
  2. EP241107a: AKO Optical Afterglow Detection
  3. Konus-Wind detection of GRB 241105A (short with extended emission)
  4. Konus-Wind detection of GRB 241021A
  5. Fermi GRB 241105A: Global MASTER-Net observations report
  6. EP241104a: EP detection of GRB 241104A X-ray emission
  7. Fermi GRB 241104A: Global MASTER-Net observations report
  8. EP241103a: GIT optical upper limit
  9. EP241021a: OHP/T193 further optical observations
  10. Fermi trigger No 752365806: Global MASTER-Net observations report
  11. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  12. EP241101a: OHP/T193 optical observations
  13. EP241103a: EP observation update
  14. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  15. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  16. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  17. EP241103a: Global MASTER-Net observations report
  18. EP241103a: an X-ray transient detected by Einstein Probe
  19. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  20. EP241021a: Upper limit from Konus-Wind observations
  21. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  22. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  23. EP241026b: Liverpool Telescope optical follow-up
  24. Fermi trigger No 752083996: Global MASTER-Net observations report
  25. GRB 241030A: SAO RAS optical observations
  26. GRB 241030A: Fermi GBM Observation
  27. EP241021a: AMI-LA radio detection
  28. GRB 241030B : GIT optical upper limits
  29. EP EP241030a: Global MASTER-Net observations report
  30. Fermi trigger No 752006065: Global MASTER-Net observations report
  31. Swift GRB241030.77: Global MASTER-Net observations report
  32. GRB241030B: Fermi GBM Observation
  33. GRB 241030B: BTA observations
  34. GRB 241030B: optical observations from the INAF Asiago Observatory
  35. GRB 241030B: Nanshan/HMT optical afterglow detection
  36. Konus-Wind detection of GRB 241030A
  37. GRB 241030B: Swift detection of a burst
  38. GRB 241030B: Fermi GBM Final Real-time Localization
  39. GRB 241030A: Fermi-LAT detection
  40. GRB 241030A: Swift/UVOT Detection
  41. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  42. EP241021a: ATCA radio observations
  43. GRB 241029A: Fermi GBM Observation
  44. Fermi trigger No 751861204: Global MASTER-Net observations report
  45. Konus-Wind detection of GRB 241025A
  46. GRB 241025A: further SAO RAS optical observations
  47. GRB 241026A: BTA and Zeiss-1000 optical observations
  48. GRB 241026A Fermi GBM Analysis
  49. GRB 241025A: SAO RAS optical observations
  50. EP241021a: further SAO RAS optical observations
  51. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  52. GRB 241026A: Swift-XRT refined Analysis
  53. GRB 241026A: SAO RAS observations of possible optical afterglow
  54. GRB 241026A: Swift detection of a burst
  55. Swift GRB241026.95: Global MASTER-Net observations report
  56. GRB241025A: 1.3m DFOT optical afterglow detection
  57. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  58. Fermi trigger No 751554401: Global MASTER-Net observations report
  59. Fermi GRB 241025A: Global MASTER-Net observations report
  60. GRB 241001A: ATCA radio observations
  61. EP241021a: VLT/FORS2 redshift z = 0.75
  62. Fermi trigger No 751449953: Global MASTER-Net observations report
  63. EP241021a: SAO RAS optical observations
  64. EP241021a: EP-FXT follow-up observation update
  65. GRB241017A: 1.3m DFOT optical upper limit
  66. EP241021a: EP detection of a fast X-ray transient
  67. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  68. Konus-Wind detection of GRB 241018A
  69. GRB 241018A/sb24101802: Mephisto optical upper limit
  70. GRB 240727A: VIRT Optical Upper Limit
  71. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  72. Fermi trigger No 750788395: Global MASTER-Net observations report
  73. Fermi GRB 241016B: Global MASTER-Net observations report
  74. Fermi GRB 241016A: Global MASTER-Net observations report
  75. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  76. GRB241013A: REM observations
  77. GRB 241013A: a long GRB detected by INTEGRAL
  78. LIGO/Virgo/KAGRA S241011k: NED Galaxies in the Localization Volume
  79. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  80. GRB 241011A: Fermi GBM Final Real-time Localization
  81. GRB 241010A: Swift-XRT refined Analysis
  82. Fermi trigger No 750211959: Global MASTER-Net observations report
  83. Fermi trigger No 750291012: Global MASTER-Net observations report
  84. GRB 241010A: Swift detection of a burst with an optical counterpart
  85. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  86. GRB 241008A: Fermi-LAT detection
  87. GRB 241002B: Swift-XRT afterglow detection
  88. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  89. GRB 240910A: LBT optical observations
  90. GRB 241006A: Swift-XRT refined Analysis
  91. IceCube Alert 241006.94: Global MASTER-Net observations report
  92. GRB 241006A: Swift detection of a burst
  93. Swift GRB241006.91: Global MASTER-Net observations report
  94. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  95. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  96. Fermi trigger No 749693019: Global MASTER-Net observations report
  97. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  98. Konus-Wind detection of GRB 240926A
  99. LIGO/Virgo/KAGRA S240925n: NED Galaxies in the Localization Volume
  100. GRB 241002B: GOTO24gpc/AT 2024xbg follow-up observations update

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