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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"

32492 results found.

  1. GRB 260519C: SVOM/GRM observation
  2. GRB 260511A: iTelescope T-75 optical detection
  3. GRB 260520B: SVOM/GRM observation
  4. GRB 260411B: TERI Gamma-ray detection
  5. GRB 260407A: TERI Gamma-ray detection
  6. GRB 260307A: TERI Gamma-ray detection
  7. GRB 260225D: TERI Gamma-ray detection
  8. GRB 251118A: TERI Gamma-ray detection
  9. GRB 251113A: TERI Gamma-ray detection
  10. GRB 260428A: TERI Gamma-ray detection
  11. Konus-Wind detection of GRB 260519C
  12. GRB 260509A: SVOM/ECLAIRs refined analysis
  13. GRB 260519C: NuSTAR detection of prompt emission
  14. Konus-Wind detection of GRB 260518A
  15. GRB 260516D: SVOM/ECLAIRs refined analysis
  16. GRB 260515A: SVOM/ECLAIRs refined analysis
  17. GRB 260421B: radio detection with the VLA
  18. GRID detection of GRB 260511A
  19. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  20. GRB 260509A: CrAO ZTSh optical upper limit
  21. GRB 260516D: EP-FXT follow-up observation
  22. GRB 260516D: GOTO optical counterpart detection
  23. GRB 260516D: LCO optical observations
  24. GRB 260515A: further Liverpool Telescope observations
  25. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  26. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  27. GRB 260516D: GROWTH-India Telescope optical detection
  28. GRB 260516D: SVOM/VT optical bright candidate
  29. GRB 260515A: CrAO ZTSh BVRI optical observations
  30. Fermi GRB 260516C: Global MASTER-Net observations report
  31. Konus-Wind detection of GRB 260515A
  32. GRB 260515A: Liverpool Telescope optical detection
  33. GRB 260515A: LCO optical counterpart detection
  34. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  35. GRB 260515A: EP-FXT follow-up observation
  36. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  37. EP260514a: NOT optical counterpart confirmation
  38. EP260514a: TRT optical counterpart candidate
  39. EP260514a: SVOM/VT optical candidate
  40. Fermi GRB 260516B: Global MASTER-Net observations report
  41. GRB 260515A: SVOM/VT optical observations
  42. GRB 260515A: OHP/T193 optical observations
  43. EP260514a: COLIBRÍ optical upper limits
  44. GRID detection of GRB 260507A
  45. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  46. GRB 260515A: LCO optical observations
  47. SVOM GRB 260515A: Global MASTER-Net observations report
  48. GRB 260515A: NOT optical observations.
  49. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  50. GRB 260515A: SVOM/VT optical candidate from VHF data
  51. GRB 260515A: JinShan optical counterpart candidate
  52. GRB 260510C: Glowbug gamma-ray detection
  53. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  54. EP260514a: GROWTH-India Telescope optical upper limit
  55. GRB 260511B: NOT optical observations
  56. Konus-Wind detection of GRB 260512A
  57. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  58. GRB 260511B: GMG Optical Upper Limit
  59. EP260514a: Global MASTER-Net observations report
  60. EP260512a: LCO optical upper limits
  61. IPN triangulation of GRB 260512A
  62. GRB 260511B: Mephisto multi-band optical followup
  63. Fermi GRB 260514A: Global MASTER-Net observations report
  64. GRB 260512A: AstroSat CZTI detection
  65. EP260512a: EP-FXT follow-up observation
  66. EP260507a: Xinglong Schmidt optical counterpart detection
  67. EP260512a: Global MASTER-Net observations report
  68. Fermi GRB 260513A: Global MASTER-Net observations report
  69. Fermi GRB 260512A: Global MASTER-Net observations report
  70. GRB 260511B: further SAO RAS optical observations
  71. GRB 260509A: SVOM/VT optical observations
  72. Konus-Wind detection of GRB 260511B
  73. EP260512a: COLIBRÍ optical upper limits
  74. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  75. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  76. GRB 260512A: NuSTAR detection of prompt emission
  77. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  78. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  79. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  80. GRB 260511A: Glowbug gamma-ray detection
  81. Konus-Wind detection of GRB 260511A
  82. MASS-Cube (GRID 2.0) detection of GRB 260511A
  83. MASS-Cube (GRID 2.0) detection of GRB 260507A
  84. GRB 260511B: SAO RAS optical observations
  85. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  86. GRB 260511B: FRAM-ORM optical detection
  87. GRB 260511A: EP-FXT follow-up observation
  88. GRB 260511B: EP-FXT follow-up observation
  89. GRB 260511B: LCO optical counterpart detection
  90. GRB260511B: MAO/AZT-22 optical observations
  91. GRB 260511A: SVOM/VT optical observations
  92. GRB 260511B: LCO optical observations
  93. GRB 260511B: OHP/T193 spectroscopic observations
  94. GRB 260511B: GOTO optical counterpart detection
  95. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  96. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  97. GRB 260511B: SVOM/VT optical observations
  98. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  99. GRB 260510B: EP-FXT follow-up observation
  100. GRB 260511B: OSIRIS+/GTC redshift z=2.006

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