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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"

19938 results found.

  1. GRB 240905E: REM optical/NIR upper limits
  2. GRB 240905E: Swift-XRT refined Analysis
  3. GRB 240905E: SVOM/GRM observation
  4. GRB 240905E: LCOGT Optical Upper Limit
  5. GRB 240905E: Swift/UVOT Upper Limits
  6. GRB 240905E: SAO RAS optical upper limit
  7. GRB 240905E: Nanshan/HMT optical upper limit
  8. Swift GRB 240905E: Global MASTER-Net observations report
  9. GRB 240905E: Swift detection of a burst
  10. GRB 240819A: Optical upper limits from TESS
  11. Swift GRB 240904A: Global MASTER-Net observations report
  12. GRB 240904A: Swift detection of a burst
  13. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  14. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  15. GRB 240828A: GECAM detection
  16. GRB 240825A: MeerLICHT afterglow detection
  17. GRB240828B: REM optical/NIR upper limits
  18. GRB 240828B: AbAO optical upper limit
  19. GRB 240828B: Mephisto optical upper limit
  20. GRB 240828B: GRANDMA Optical Upper Limit
  21. GRB 240829A: Swift-BAT refined analysis
  22. GRB 240825A: Swift-BAT refined analysis
  23. GRB 240828B: J-band upper limit from WINTER
  24. GRB 240828B: GMG Optical Upper Limit
  25. GRB 240828B: KAIT optical upper limit
  26. GRB 240828A: Fermi GBM Observation
  27. GRB 240828A: Swift-XRT afterglow detection
  28. GRB 240828B: Swift-XRT afterglow detection
  29. GRB 240829A: Swift detection of a burst
  30. Swift GRB240829.16: Global MASTER-Net observations report
  31. GRB 240828A: Fermi-LAT detection
  32. GRB 240828A: Tiled Swift observations
  33. GRB 240825A: Upper limits from a neutrino search with IceCube
  34. GRB 240819A as a likely X-Ray Flash
  35. GRB 240828B: Swift ToO observations
  36. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  37. GRB 240825A: GECAM detection
  38. GRB 240824A: GIT optical upper limit
  39. GRB 240819A: Swift afterglow confirmation
  40. GRB 240824B: Ondrejov D50 optical limit
  41. GRB 240825A: PRIME near-infrared detection
  42. Konus-Wind detection of GRB 240825A (bright/long)
  43. GRB 240825A: Fermi GBM Observation
  44. GRB 240825A: AKO Optical Follow-Up Observations
  45. GRB 240825A: AstroSat CZTI detection of the long bright burst
  46. SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
  47. GRB 240825A: Swift/UVOT Detection
  48. GRB 240825A: REM detection of the optical/NIR afterglow
  49. GRB 240825A: Swift-XRT refined Analysis
  50. GRB 240825A: VLT/X-shooter redshift
  51. GRB 240825A: SVOM/C-GFT optical observations
  52. GRB 240825A: Montarrenti Observatory optical observations
  53. GRB 240825A: Enhanced Swift-XRT position
  54. GRB 240825A: MASTER optical counterpart observation
  55. GRB 240825A: Fermi-LAT detection
  56. GRB 240825A: LCO optical observations
  57. GRB 240824B: KAIT optical upper limit
  58. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  59. GRB 240824B: Fermi GBM Observation
  60. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  61. GRB 240825A: GMG Optical Observation
  62. Swift GRB 240825A: Global MASTER-Net observations report
  63. GRB 240825A: 1.6m Mephisto multi-band detection
  64. GRB 240825A: AKO Optical Afterglow Detection
  65. GRB 240825A: Skynet Optical Afterglow observations
  66. GRB 240825A: Nanshan/HMT optical afterglow observations
  67. GRB 240825A: Swift detection of a burst with a bright optical counterpart
  68. GRB 240824A: Swift-BAT refined analysis
  69. GRB 240824A: SVOM/C-GFT optical upper limit
  70. GRB 240824B: Swift-XRT afterglow detection
  71. GRB 240824A: Swift-XRT observations
  72. GRB 240824B: Swift/BAT arcminute localization of a burst
  73. GRB 240824B: Swift ToO observations
  74. GRB 240824A: Swift/UVOT Upper Limits
  75. GRB 240821A: Swift/UVOT observations of the XRT sources.
  76. GRB240824A: GRANDMA/TAROT-TCA Upper Limit
  77. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  78. GRB 240824A: KAIT optical upper limit
  79. GRB 240824A: Skynet Optical Afterglow Discovery
  80. GRB 240824A: Swift detection of a burst
  81. Swift GRB240824.04: Global MASTER-Net observations report
  82. SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
  83. GRB 240821A: Colibri Optical Upper Limit
  84. GRB 240821A: Swift-XRT observations
  85. GRB 240821A: REM optical/NIR upper limits
  86. GRB 240821A: JinShan optical upper limits
  87. GRB 240809A: Mondy and AbAO Optical Observations
  88. GRB 240821A: SVOM/VT follow-up and optical upper limit
  89. GRB 240821A: GMG Optical Upper Limit
  90. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  91. GRB 240821A: Swift ToO observations
  92. Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
  93. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  94. GRB 240819A: Swift-XRT observations
  95. GRB 240819A: JinShan optical upper limits on one Swift/XRT source
  96. GRB 240819A: KAIT optical upper limit
  97. Trigger 1249653: Swift detection of SGR 1E 1841-045 / Kes 73
  98. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  99. GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
  100. GRB 240819A: Swift ToO observations

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