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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"

35429 results found.

  1. Konus-Wind detection of GRB 241021A
  2. GRB 241105A: SVOM/VT optical afterglow observations
  3. GRB 241105A: Swift-XRT afterglow detection
  4. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  5. GRB 241104A: Swift-XRT observations
  6. GRB 240511A: LCO upper limits
  7. GRB 241104A: Fermi GBM Observation
  8. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  9. GRB 241105A: Swift ToO observations
  10. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  11. GRB 241104A: Swift ToO observations
  12. GRB 241104A: NOT optical non-detection
  13. GRB 241105A: GOTO tentative optical counterpart candidate
  14. Fermi GRB 241105A: Global MASTER-Net observations report
  15. GRB 241104A: SVOM/VT optical candidate
  16. GRB 241105A: Fermi GBM Final Real-time Localization
  17. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  18. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  19. GRB 241104A: SVOM/GRM observation
  20. EP241104a: EP detection of GRB 241104A X-ray emission
  21. GRB 241010A: host galaxy redshift z = 0.977
  22. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  23. GRB 240821A: further radio observations with the VLA
  24. Fermi GRB 241104A: Global MASTER-Net observations report
  25. GRB 241104A: Fermi GBM Final Real-time Localization
  26. GRB 241030A: GRBAlpha detection
  27. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  28. GRB 241030A: Rapid release of TESS data.
  29. GRB 241029A: GRBAlpha detection
  30. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  31. Swift GRB 241101A: Global MASTER-Net observations report
  32. GRB 241101A: FRAM-ORM optical limit
  33. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  34. EP241021a: Upper limit from Konus-Wind observations
  35. GRB 241101A: Swift-BAT refined analysis
  36. GRB 241030A: further SAO RAS optical observations
  37. GRB 241030A: Optical Observations via Virtual Telescope Project
  38. GRB 241030B: Swift-XRT refined Analysis
  39. GRB 241026A: SAO RAS optical observations
  40. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  41. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  42. GRB 241101A: Swift detection of a burst
  43. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  44. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  45. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  46. GRB 241030B: Montarrenti Observatory optical upper limit
  47. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  48. GRB 241030A: SAO RAS optical observations
  49. GRB 241030A: Fermi GBM Observation
  50. GRB 241030B : GIT optical upper limits
  51. GRB 241030B: LCOGT Optical Upper Limits
  52. GRB 241030B: Swift-BAT refined analysis
  53. GRB 241030A: Swift-BAT refined analysis
  54. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  55. GRB 241030B: Swift/UVOT Detection
  56. GRB 241029A: LCO optical detection
  57. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  58. GRB 241030B: SVOM/GRM observation
  59. GRB 241030B : MITSuME Akeno optical upper limits
  60. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  61. GRB 241030B: SVOM/VT optical afterglow observations
  62. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  63. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  64. GRB241030B: Fermi GBM Observation
  65. GRB 241030B: BTA observations
  66. GRB 241029A: SVOM/VT optical afterglow observations
  67. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  68. GRB 241030B: Enhanced Swift-XRT position
  69. GRB 241030B: optical observations from the INAF Asiago Observatory
  70. GRB241030B: GRANDMA/TAROT Upper Limit
  71. GRB 241030A: Swift-XRT refined Analysis
  72. GRB 241030B: SAO RAS optical observations
  73. GRB 241030B: AKO Optical Afterglow Detection
  74. GRB 241030B: Nanshan/HMT optical afterglow detection
  75. GRB 241030B: SVOM/ECLAIRs detection of a burst
  76. GRB 241030B: Prompt enhanced Swift-XRT position
  77. Konus-Wind detection of GRB 241030A
  78. GRB 241030B: Swift detection of a burst
  79. GRB 241030B: Fermi GBM Final Real-time Localization
  80. GRB 241030A: Fermi-LAT detection
  81. GRB 240912A: radio detection with the VLA
  82. Fermi GRB 241030A: Global MASTER-Net observations report
  83. GRB 241030A: AKO Optical Afterglow Detection
  84. Swift GRB 241030A: Global MASTER-Net observations report
  85. GRB 241030A: Swift/UVOT Detection
  86. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  87. GRB 241030A: SVOM/GRM observation
  88. GRB 241026A: Swift-BAT refined analysis
  89. GRB 241030A: SVOM/C-GFT optical observations
  90. GRB 241026A: LBT optical observations
  91. GRB 241030A: Multiband optical detection with Mephisto
  92. GRB 241030A: SVOM/VT optical afterglow observations
  93. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  94. GRB 241030A : MITSuME Akeno optical afterglow detection
  95. GRB 241030A: Enhanced Swift-XRT position
  96. GRB 241029A: GROWTH-India Telescope optical follow up
  97. GRB 241030A: TRT optical observations
  98. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  99. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  100. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart

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