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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32499 results found.

  1. Fermi GRB 260523A: Global MASTER-Net observations report
  2. GRB 260522A: Fermi GBM Observation
  3. GRB 260522B: NuSTAR detection of prompt emission
  4. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  5. GRB 260522A: GOTO optical upper limit
  6. Fermi GRB 260522A: Global MASTER-Net observations report
  7. GRB 260522A: Fermi-LAT detection
  8. GRB 260519C: SVOM/GRM observation
  9. GRB 260511A: iTelescope T-75 optical detection
  10. GRB 260520B: SVOM/GRM observation
  11. GRB 260411B: TERI Gamma-ray detection
  12. GRB 260407A: TERI Gamma-ray detection
  13. GRB 260307A: TERI Gamma-ray detection
  14. GRB 260225D: TERI Gamma-ray detection
  15. GRB 251118A: TERI Gamma-ray detection
  16. GRB 251113A: TERI Gamma-ray detection
  17. GRB 260428A: TERI Gamma-ray detection
  18. Konus-Wind detection of GRB 260519C
  19. GRB 260509A: SVOM/ECLAIRs refined analysis
  20. GRB 260519C: NuSTAR detection of prompt emission
  21. Konus-Wind detection of GRB 260518A
  22. GRB 260516D: SVOM/ECLAIRs refined analysis
  23. GRB 260515A: SVOM/ECLAIRs refined analysis
  24. GRB 260421B: radio detection with the VLA
  25. GRID detection of GRB 260511A
  26. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  27. GRB 260509A: CrAO ZTSh optical upper limit
  28. GRB 260516D: EP-FXT follow-up observation
  29. GRB 260516D: GOTO optical counterpart detection
  30. GRB 260516D: LCO optical observations
  31. GRB 260515A: further Liverpool Telescope observations
  32. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  33. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  34. GRB 260516D: GROWTH-India Telescope optical detection
  35. GRB 260516D: SVOM/VT optical bright candidate
  36. GRB 260515A: CrAO ZTSh BVRI optical observations
  37. Fermi GRB 260516C: Global MASTER-Net observations report
  38. Konus-Wind detection of GRB 260515A
  39. GRB 260515A: Liverpool Telescope optical detection
  40. GRB 260515A: LCO optical counterpart detection
  41. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  42. GRB 260515A: EP-FXT follow-up observation
  43. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  44. EP260514a: NOT optical counterpart confirmation
  45. EP260514a: TRT optical counterpart candidate
  46. EP260514a: SVOM/VT optical candidate
  47. Fermi GRB 260516B: Global MASTER-Net observations report
  48. GRB 260515A: SVOM/VT optical observations
  49. GRB 260515A: OHP/T193 optical observations
  50. EP260514a: COLIBRÍ optical upper limits
  51. GRID detection of GRB 260507A
  52. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  53. GRB 260515A: LCO optical observations
  54. SVOM GRB 260515A: Global MASTER-Net observations report
  55. GRB 260515A: NOT optical observations.
  56. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  57. GRB 260515A: SVOM/VT optical candidate from VHF data
  58. GRB 260515A: JinShan optical counterpart candidate
  59. GRB 260510C: Glowbug gamma-ray detection
  60. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  61. EP260514a: GROWTH-India Telescope optical upper limit
  62. GRB 260511B: NOT optical observations
  63. Konus-Wind detection of GRB 260512A
  64. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  65. GRB 260511B: GMG Optical Upper Limit
  66. EP260514a: Global MASTER-Net observations report
  67. EP260512a: LCO optical upper limits
  68. IPN triangulation of GRB 260512A
  69. GRB 260511B: Mephisto multi-band optical followup
  70. Fermi GRB 260514A: Global MASTER-Net observations report
  71. GRB 260512A: AstroSat CZTI detection
  72. EP260512a: EP-FXT follow-up observation
  73. EP260507a: Xinglong Schmidt optical counterpart detection
  74. EP260512a: Global MASTER-Net observations report
  75. Fermi GRB 260513A: Global MASTER-Net observations report
  76. Fermi GRB 260512A: Global MASTER-Net observations report
  77. GRB 260511B: further SAO RAS optical observations
  78. GRB 260509A: SVOM/VT optical observations
  79. Konus-Wind detection of GRB 260511B
  80. EP260512a: COLIBRÍ optical upper limits
  81. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  82. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  83. GRB 260512A: NuSTAR detection of prompt emission
  84. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  85. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  86. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  87. GRB 260511A: Glowbug gamma-ray detection
  88. Konus-Wind detection of GRB 260511A
  89. MASS-Cube (GRID 2.0) detection of GRB 260511A
  90. MASS-Cube (GRID 2.0) detection of GRB 260507A
  91. GRB 260511B: SAO RAS optical observations
  92. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  93. GRB 260511B: FRAM-ORM optical detection
  94. GRB 260511A: EP-FXT follow-up observation
  95. GRB 260511B: EP-FXT follow-up observation
  96. GRB 260511B: LCO optical counterpart detection
  97. GRB260511B: MAO/AZT-22 optical observations
  98. GRB 260511A: SVOM/VT optical observations
  99. GRB 260511B: LCO optical observations
  100. GRB 260511B: OHP/T193 spectroscopic observations

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