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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"

32502 results found.

  1. Fermi GRB 260525A: Global MASTER-Net observations report
  2. GRB 260523B: AstroSat CZTI detection
  3. GRB 260523B: GECAM-B observation
  4. Fermi GRB 260523A: Global MASTER-Net observations report
  5. GRB 260522A: Fermi GBM Observation
  6. GRB 260522B: NuSTAR detection of prompt emission
  7. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  8. GRB 260522A: GOTO optical upper limit
  9. Fermi GRB 260522A: Global MASTER-Net observations report
  10. GRB 260522A: Fermi-LAT detection
  11. GRB 260519C: SVOM/GRM observation
  12. GRB 260511A: iTelescope T-75 optical detection
  13. GRB 260520B: SVOM/GRM observation
  14. GRB 260411B: TERI Gamma-ray detection
  15. GRB 260407A: TERI Gamma-ray detection
  16. GRB 260307A: TERI Gamma-ray detection
  17. GRB 260225D: TERI Gamma-ray detection
  18. GRB 251118A: TERI Gamma-ray detection
  19. GRB 251113A: TERI Gamma-ray detection
  20. GRB 260428A: TERI Gamma-ray detection
  21. Konus-Wind detection of GRB 260519C
  22. GRB 260509A: SVOM/ECLAIRs refined analysis
  23. GRB 260519C: NuSTAR detection of prompt emission
  24. Konus-Wind detection of GRB 260518A
  25. GRB 260516D: SVOM/ECLAIRs refined analysis
  26. GRB 260515A: SVOM/ECLAIRs refined analysis
  27. GRB 260421B: radio detection with the VLA
  28. GRID detection of GRB 260511A
  29. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  30. GRB 260509A: CrAO ZTSh optical upper limit
  31. GRB 260516D: EP-FXT follow-up observation
  32. GRB 260516D: GOTO optical counterpart detection
  33. GRB 260516D: LCO optical observations
  34. GRB 260515A: further Liverpool Telescope observations
  35. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  36. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  37. GRB 260516D: GROWTH-India Telescope optical detection
  38. GRB 260516D: SVOM/VT optical bright candidate
  39. GRB 260515A: CrAO ZTSh BVRI optical observations
  40. Fermi GRB 260516C: Global MASTER-Net observations report
  41. Konus-Wind detection of GRB 260515A
  42. GRB 260515A: Liverpool Telescope optical detection
  43. GRB 260515A: LCO optical counterpart detection
  44. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  45. GRB 260515A: EP-FXT follow-up observation
  46. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  47. EP260514a: NOT optical counterpart confirmation
  48. EP260514a: TRT optical counterpart candidate
  49. EP260514a: SVOM/VT optical candidate
  50. Fermi GRB 260516B: Global MASTER-Net observations report
  51. GRB 260515A: SVOM/VT optical observations
  52. GRB 260515A: OHP/T193 optical observations
  53. EP260514a: COLIBRÍ optical upper limits
  54. GRID detection of GRB 260507A
  55. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  56. GRB 260515A: LCO optical observations
  57. SVOM GRB 260515A: Global MASTER-Net observations report
  58. GRB 260515A: NOT optical observations.
  59. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  60. GRB 260515A: SVOM/VT optical candidate from VHF data
  61. GRB 260515A: JinShan optical counterpart candidate
  62. GRB 260510C: Glowbug gamma-ray detection
  63. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  64. EP260514a: GROWTH-India Telescope optical upper limit
  65. GRB 260511B: NOT optical observations
  66. Konus-Wind detection of GRB 260512A
  67. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  68. GRB 260511B: GMG Optical Upper Limit
  69. EP260514a: Global MASTER-Net observations report
  70. EP260512a: LCO optical upper limits
  71. IPN triangulation of GRB 260512A
  72. GRB 260511B: Mephisto multi-band optical followup
  73. Fermi GRB 260514A: Global MASTER-Net observations report
  74. GRB 260512A: AstroSat CZTI detection
  75. EP260512a: EP-FXT follow-up observation
  76. EP260507a: Xinglong Schmidt optical counterpart detection
  77. EP260512a: Global MASTER-Net observations report
  78. Fermi GRB 260513A: Global MASTER-Net observations report
  79. Fermi GRB 260512A: Global MASTER-Net observations report
  80. GRB 260511B: further SAO RAS optical observations
  81. GRB 260509A: SVOM/VT optical observations
  82. Konus-Wind detection of GRB 260511B
  83. EP260512a: COLIBRÍ optical upper limits
  84. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  85. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  86. GRB 260512A: NuSTAR detection of prompt emission
  87. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  88. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  89. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  90. GRB 260511A: Glowbug gamma-ray detection
  91. Konus-Wind detection of GRB 260511A
  92. MASS-Cube (GRID 2.0) detection of GRB 260511A
  93. MASS-Cube (GRID 2.0) detection of GRB 260507A
  94. GRB 260511B: SAO RAS optical observations
  95. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  96. GRB 260511B: FRAM-ORM optical detection
  97. GRB 260511A: EP-FXT follow-up observation
  98. GRB 260511B: EP-FXT follow-up observation
  99. GRB 260511B: LCO optical counterpart detection
  100. GRB260511B: MAO/AZT-22 optical observations

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