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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"

28879 results found.

  1. GRB 260924A: VLA detection
  2. GRB 260924A: Swift/UVOT UV grism spectrum results
  3. GRB 260924A: AbAO optical observations
  4. Fermi GRB 260928A: Global MASTER-Net observations report
  5. GRB 260928A: Fermi GBM Final Real-time Localization
  6. EP260924a: Global MASTER-Net observations report
  7. GRB 260925A: Swift-BAT refined analysis
  8. Swift Trigger 1513439: consistent with noise and not astrophysical
  9. GRB 260924A: Upper limits from a neutrino search with IceCube
  10. Fermi GRB 260926C: Global MASTER-Net observations report
  11. GRB 260926C: Fermi GBM Final Real-time Localization
  12. GRB260914A: MAO/AZT-22 optical observations
  13. GRB 260926B: Fermi GBM Final Real-time Localization
  14. Fermi GRB 260926A: Global MASTER-Net observations report
  15. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  16. GRB 260926A: Fermi GBM Final Real-time Localization
  17. The EP-WXT trigger 01709320726 is likely a flaring star
  18. GRB 260924A: COLIBRÍ optical observations
  19. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  20. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  21. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  22. GRB 260925A: Swift-XRT refined Analysis
  23. Swift Trigger 1513439 is probably not a GRB
  24. GRB 260925A: Swift/UVOT Upper Limits
  25. Konus-Wind detection of GRB 260924A
  26. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  27. GRB 260923A: Glowbug gamma-ray detection
  28. GRB 260924A: Optical follow-up observations with Kinder
  29. GRB 260925A: COLIBRÍ optical upper limits
  30. GRB 260925A: FRAM-Auger optical limit
  31. GRB 260924A: Ondrejov D50 optical afterglow detection
  32. EP260924a: J-band upper limit with WINTER
  33. GRB 260924A: SVOM/GRM observation
  34. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  35. GRB 260925A: Swift detection of a burst
  36. GRB 260923A: Insight-HXMT/HE detection
  37. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  38. GRB 260924A: Swift/UVOT Detection
  39. GRB 260924A: GROWTH-India Telescope optical observations
  40. GRB 260924A: Swift-BAT refined analysis
  41. GRB 260924A: NuSTAR detection of prompt emission
  42. GRB 260924A: Swift-XRT refined Analysis
  43. GRB 260921A: NuSTAR detection of prompt emission
  44. GRB 260921A: SVOM/GRM observation
  45. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  46. GRB 260924A: Fermi GRB Observation
  47. Konus-Wind detection of GRB 260921A (possible merger-origin)
  48. GRB 260924A: Fermi-LAT detection of a bright burst
  49. GRB 260924A: AstroSat CZTI detection
  50. GRB 260920A: SVOM/GRM observation
  51. GRB 260924A: NOT optical counterpart confirmation
  52. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  53. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  54. The EP-WXT trigger 01709319842 is likely a flaring star
  55. GRB 260924A: Swift detection of a burst
  56. GRB 260924A: Fermi GBM Final Real-time Localization
  57. Fermi GRB 260923A: Global MASTER-Net observations report
  58. GRB 260923A: Fermi GBM Final Real-time Localization
  59. GRB 260922A: Ondrejov D50 optical limit
  60. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  61. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  62. GRB 260922A: Swift-BAT refined analysis
  63. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  64. GRB 260922A: J-band upper limit with WINTER
  65. GRB 260922A: Swift/UVOT Upper Limits
  66. GRB 260922A: COLIBRÍ optical upper limits
  67. GRB 260922A: Swift-XRT refined Analysis
  68. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  69. GRB 260920A: Glowbug gamma-ray detection
  70. GRB 260918A: SVOM/ECLAIRs refined analysis
  71. GRB 260922A: SVOM/C-GFT optical upper limit
  72. GRB 260922A: Swift detection of a burst
  73. GRB 260917C: AstroSat CZTI detection
  74. GRB 260921A: AstroSat CZTI detection
  75. GRB 260921A: Swift-BAT refined analysis
  76. GRB 260921B: Fermi GBM Final Localization
  77. GRB 260921A: Fermi GBM Observation
  78. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  79. EP Alert 260921.58: Global MASTER-Net observations report
  80. GRB 260917B:: SVOM/ECLAIRs refined analysis
  81. The EP-WXT trigger 01709319528 is likely a flaring star
  82. EP260920a: VLT/HAWK-I near-infrared candidate
  83. Swift GRB 260921A: Global MASTER-Net observations report
  84. GRB 260921A: Swift detection of a burst
  85. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  86. GRB 260921A: Fermi GBM Final Real-time Localization
  87. EP260920b: LCO observations
  88. GRB 260920A: AstroSat CZTI detection
  89. EP260920b: SVOM/VT optical observation
  90. EP260920b: COLIBRÍ optical observations
  91. EP260920b: LCO optical counterpart detection
  92. The EP-WXT trigger 01709318601 is likely a flaring star
  93. EP Alert 260921.01: Global MASTER-Net observations report
  94. EP260920b: Global MASTER-Net observations report
  95. EP Alert 260920.66: Global MASTER-Net observations report
  96. EP260920a: NOT early time optical upper limits
  97. EP260920a: NOT optical upper limits
  98. GRB 260920A: Fermi GBM Final Real-time Localization
  99. EP260920a: SVOM/VT optical upper limits
  100. EP260917a: Global MASTER-Net observations report

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