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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"

32508 results found.

  1. GRB241030A: OHP/T193 optical observations
  2. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  3. Swift GRB 241101A: Global MASTER-Net observations report
  4. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  5. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  6. EP241021a: Upper limit from Konus-Wind observations
  7. GRB 241101A: Swift-BAT refined analysis
  8. GRB 241030A: further SAO RAS optical observations
  9. GRB 241030A: Optical Observations via Virtual Telescope Project
  10. EP241021a: Liverpool Telescope optical follow-up observations
  11. GRB 241026A: SAO RAS optical observations
  12. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  13. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  14. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  15. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  16. EP241021a: OHP/T193 optical observations
  17. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  18. GRB 241030B: Montarrenti Observatory optical upper limit
  19. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  20. EP241026b: Liverpool Telescope optical follow-up
  21. GRB 241030A: SAO RAS optical observations
  22. GRB 241030A: Fermi GBM Observation
  23. EP241021a: AMI-LA radio detection
  24. GRB 241030B : GIT optical upper limits
  25. GRB 241030B: LCOGT Optical Upper Limits
  26. GRB 241030B: Swift-BAT refined analysis
  27. GRB 241030A: Swift-BAT refined analysis
  28. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  29. GRB 241030B: Swift/UVOT Detection
  30. EP EP241030a: Global MASTER-Net observations report
  31. GRB 241029A: LCO optical detection
  32. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  33. GRB 241030B: SVOM/GRM observation
  34. GRB 241030B : MITSuME Akeno optical upper limits
  35. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  36. GRB 241030B: SVOM/VT optical afterglow observations
  37. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  38. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  39. GRB241030B: Fermi GBM Observation
  40. GRB 241030B: BTA observations
  41. GRB 241029A: SVOM/VT optical afterglow observations
  42. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  43. GRB 241030B: optical observations from the INAF Asiago Observatory
  44. EP241021a: Swift-UVOT detection
  45. GRB241030B: GRANDMA/TAROT Upper Limit
  46. GRB 241030B: SAO RAS optical observations
  47. GRB 241030B: AKO Optical Afterglow Detection
  48. GRB 241030B: Nanshan/HMT optical afterglow detection
  49. GRB 241030B: SVOM/ECLAIRs detection of a burst
  50. Konus-Wind detection of GRB 241030A
  51. GRB 241030A: Fermi-LAT detection
  52. GRB 240912A: radio detection with the VLA
  53. Fermi GRB 241030A: Global MASTER-Net observations report
  54. GRB 241030A: AKO Optical Afterglow Detection
  55. Swift GRB 241030A: Global MASTER-Net observations report
  56. GRB 241030A: Swift/UVOT Detection
  57. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  58. GRB 241030A: SVOM/GRM observation
  59. GRB 241026A: Swift-BAT refined analysis
  60. GRB 241030A: SVOM/C-GFT optical observations
  61. GRB 241026A: LBT optical observations
  62. EP241021a: Optical rebrightening observations with Mephisto
  63. EP241026b: EP-FXT follow-up observation
  64. GRB 241030A: Multiband optical detection with Mephisto
  65. GRB 241030A: SVOM/VT optical afterglow observations
  66. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  67. GRB 241030A : MITSuME Akeno optical afterglow detection
  68. GRB 241029A: GROWTH-India Telescope optical follow up
  69. GRB 241030A: TRT optical observations
  70. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  71. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  72. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  73. GRB 241029A: SAO RAS optical observations
  74. GRB 241026A: SAO RAS optical observations
  75. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  76. EP241021a: SAO RAS observations of rebrightening
  77. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  78. EP241021a: ATCA radio observations
  79. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  80. GRB 241026A: Swift/UVOT Upper Limits
  81. GRB 241029A: Swift-XRT observations
  82. GRB 241029A: Fermi GBM Observation
  83. GRB 241029A: AKO Optical Afterglow Detection
  84. GRB 241029A: GOTO optical afterglow detection
  85. EP241021a: continued SOAR observations confirm optical rebrightening
  86. GRB 241029A: MASTER early optical counterpart detection
  87. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  88. GRB 241029A: Mephisto observations
  89. EP 241026b: LBT possible optical counterpart (brightening source)
  90. GRB 241029A: TRT optical afterglow candidate detection
  91. GRB 241029A: Swift ToO observations
  92. GRB 241029A: SVOM/GRM observation
  93. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  94. GRB 240821A: Keck/LRIS spectroscopic observations
  95. EP241021a: Gemini-South detection of optical rebrightening
  96. GRB 241026A: the 100th GRB detected by GRBAlpha
  97. GRB 241026A: TNOT optical counterpart detection
  98. Konus-Wind detection of GRB 241025A
  99. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  100. GRB 241026A: LBT redshift confirmation

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