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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 241029A: GRBAlpha detection
  2. EP241101a: BOOTES-7 optical upper limit
  3. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  4. S241102cy: Identification of a GW compact binary merger candidate
  5. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  6. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  7. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  8. GRB241030A: OHP/T193 optical observations
  9. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  10. EP241101a: EP-WXT detection of a fast X-ray transient
  11. Swift GRB 241101A: Global MASTER-Net observations report
  12. GRB 241101A: FRAM-ORM optical limit
  13. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  14. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  15. EP241021a: Upper limit from Konus-Wind observations
  16. GRB 241101A: Swift-BAT refined analysis
  17. GRB 241030A: further SAO RAS optical observations
  18. GRB 241030A: Optical Observations via Virtual Telescope Project
  19. EP241021a: Liverpool Telescope optical follow-up observations
  20. GRB 241030B: Swift-XRT refined Analysis
  21. GRB 241026A: SAO RAS optical observations
  22. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  23. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  24. GRB 241101A: Swift detection of a burst
  25. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  26. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  27. EP241021a: OHP/T193 optical observations
  28. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  29. GRB 241030B: Montarrenti Observatory optical upper limit
  30. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  31. EP241026b: Liverpool Telescope optical follow-up
  32. Fermi trigger No 752083996: Global MASTER-Net observations report
  33. GRB 241030A: SAO RAS optical observations
  34. GRB 241030A: Fermi GBM Observation
  35. EP241021a: AMI-LA radio detection
  36. GRB 241030B : GIT optical upper limits
  37. GRB 241030B: LCOGT Optical Upper Limits
  38. GRB 241030B: Swift-BAT refined analysis
  39. GRB 241030A: Swift-BAT refined analysis
  40. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  41. GRB 241030B: Swift/UVOT Detection
  42. EP EP241030a: Global MASTER-Net observations report
  43. GRB 241029A: LCO optical detection
  44. Fermi trigger No 752006065: Global MASTER-Net observations report
  45. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  46. Swift GRB241030.77: Global MASTER-Net observations report
  47. GRB 241030B: SVOM/GRM observation
  48. GRB 241030B : MITSuME Akeno optical upper limits
  49. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  50. GRB 241030B: SVOM/VT optical afterglow observations
  51. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  52. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  53. GRB241030B: Fermi GBM Observation
  54. GRB 241030B: BTA observations
  55. GRB 241029A: SVOM/VT optical afterglow observations
  56. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  57. GRB 241030B: Enhanced Swift-XRT position
  58. GRB 241030B: optical observations from the INAF Asiago Observatory
  59. EP241021a: Swift-UVOT detection
  60. GRB241030B: GRANDMA/TAROT Upper Limit
  61. GRB 241030A: Swift-XRT refined Analysis
  62. GRB 241030B: SAO RAS optical observations
  63. GRB 241030B: AKO Optical Afterglow Detection
  64. GRB 241030B: Nanshan/HMT optical afterglow detection
  65. GRB 241030B: SVOM/ECLAIRs detection of a burst
  66. GRB 241030B: Prompt enhanced Swift-XRT position
  67. Konus-Wind detection of GRB 241030A
  68. GRB 241030B: Swift detection of a burst
  69. GRB 241030B: Fermi GBM Final Real-time Localization
  70. GRB 241030A: Fermi-LAT detection
  71. GRB 240912A: radio detection with the VLA
  72. Fermi GRB 241030A: Global MASTER-Net observations report
  73. GRB 241030A: AKO Optical Afterglow Detection
  74. Swift GRB 241030A: Global MASTER-Net observations report
  75. GRB 241030A: Swift/UVOT Detection
  76. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  77. GRB 241030A: SVOM/GRM observation
  78. GRB 241026A: Swift-BAT refined analysis
  79. GRB 241030A: SVOM/C-GFT optical observations
  80. GRB 241026A: LBT optical observations
  81. EP241021a: Optical rebrightening observations with Mephisto
  82. EP241026b: EP-FXT follow-up observation
  83. GRB 241030A: Multiband optical detection with Mephisto
  84. GRB 241030A: SVOM/VT optical afterglow observations
  85. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  86. GRB 241030A : MITSuME Akeno optical afterglow detection
  87. GRB 241030A: Enhanced Swift-XRT position
  88. GRB 241029A: GROWTH-India Telescope optical follow up
  89. GRB 241030A: TRT optical observations
  90. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  91. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  92. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  93. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  94. GRB 241030A: Fermi GBM Final Real-time Localization
  95. GRB 241029A: SAO RAS optical observations
  96. GRB 241026A: SAO RAS optical observations
  97. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  98. EP241021a: SAO RAS observations of rebrightening
  99. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  100. EP241021a: ATCA radio observations

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