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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"

23410 results found.

  1. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  2. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  3. EP260526a: SVOM/VT optical upper limits
  4. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  5. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  6. EP260527a/GRB 260527A: EP-FXT follow-up observation
  7. EP260527a: SVOM/VT optical observation
  8. EP260527a: COLIBRÍ optical detection
  9. EP260527a: Einstein Probe detection of a fast X-ray transient
  10. EP260526a: LCO optical upper limits
  11. EP260526a: Einstein Probe detection of a fast X-ray transient
  12. EP260526.405: COLIBRÍ optical upper limits
  13. The EP-WXT trigger 01709266106 is not a real source
  14. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  15. EP-WXT 01709266106: NOT optical upper limits
  16. GRB 260522A: Fermi GBM Observation
  17. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  18. GRB 260511A: iTelescope T-75 optical detection
  19. GRB 260520B: SVOM/GRM observation
  20. GRB 260411B: TERI Gamma-ray detection
  21. GRB 260407A: TERI Gamma-ray detection
  22. GRB 260307A: TERI Gamma-ray detection
  23. GRB 260225D: TERI Gamma-ray detection
  24. GRB 251118A: TERI Gamma-ray detection
  25. GRB 251113A: TERI Gamma-ray detection
  26. GRB 260428A: TERI Gamma-ray detection
  27. GRB 260518A: AstroSat CZTI detection of a long burst
  28. GRB 260421B: radio detection with the VLA
  29. GRB 260509A: CrAO ZTSh optical upper limit
  30. GRB 260516D: GOTO optical counterpart detection
  31. GRB 260516D: LCO optical observations
  32. GRB 260515A: further Liverpool Telescope observations
  33. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  34. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  35. GRB 260516D: GROWTH-India Telescope optical detection
  36. GRB 260516D: SVOM/VT optical bright candidate
  37. GRB 260515A: CrAO ZTSh BVRI optical observations
  38. GRB 260515A: LCO optical counterpart detection
  39. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  40. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  41. EP260514a: NOT optical counterpart confirmation
  42. EP260514a: TRT optical counterpart candidate
  43. EP260514a: SVOM/VT optical candidate
  44. GRB 260515A: OHP/T193 optical observations
  45. EP260514a: COLIBRÍ optical upper limits
  46. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  47. GRB 260515A: LCO optical observations
  48. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  49. GRB 260515A: SVOM/VT optical candidate from VHF data
  50. GRB 260515A: JinShan optical counterpart candidate
  51. GRB 260515A: SVOM detection of a burst
  52. GRB 260510C: Glowbug gamma-ray detection
  53. EP260514a: GROWTH-India Telescope optical upper limit
  54. GRB 260511B: NOT optical observations
  55. GRB 260511B: GMG Optical Upper Limit
  56. EP260514a: Einstein Probe detection of a fast X-ray transient
  57. EP260512a: LCO optical upper limits
  58. IPN triangulation of GRB 260512A
  59. GRB 260511B: Mephisto multi-band optical followup
  60. EP260512a: EP-FXT follow-up observation
  61. EP260507a: Xinglong Schmidt optical counterpart detection
  62. GRB 260511B: further SAO RAS optical observations
  63. EP260512a: COLIBRÍ optical upper limits
  64. EP260512a: Einstein Probe detection of an X-ray transient
  65. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  66. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  67. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  68. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  69. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  70. GRB 260511A: Glowbug gamma-ray detection
  71. GRB 260511B: SAO RAS optical observations
  72. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  73. GRB 260511B: FRAM-ORM optical detection
  74. GRB 260511B: LCO optical counterpart detection
  75. GRB260511B: MAO/AZT-22 optical observations
  76. GRB 260511B: LCO optical observations
  77. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  78. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  79. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  80. GRB 260509A: SAO RAS optical observations
  81. GRB 260511A: REM near-infrared detection
  82. GRB 260511B: GROWTH-India Telescope optical observations
  83. GRB 260511B: AstroSat CZTI detection
  84. GRB 260506B: Glowbug gamma-ray detection
  85. GRB 260506A: Glowbug gamma-ray detection of a short burst
  86. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  87. GRB 260511B: SVOM/VT optical observation with VHF data
  88. GRB 260511B: TRT optical observation
  89. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  90. GRB 260511B SVOM/C-GFT optical counterpart detection
  91. EP260509a: LCO optical upper limits
  92. GRB 260511A: UTGO H50 optical afterglow observation
  93. GRB 260510C: AstroSat CZTI detection
  94. GRB 260511B: SVOM detection of a burst
  95. GRB 260510C: SVOM/VT optical counterpart confirmation
  96. EP260509a: EP-FXT non-detection and upper limit
  97. GRB 260511A: SVOM/VT optical observation with VHF data
  98. GRB 260511A: KAIT optical afterglow observations
  99. GRB 260511A: LCO optical afterglow detection
  100. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart

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