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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"

28053 results found.

  1. GRB 260924A: AbAO optical observations
  2. Fermi GRB 260928A: Global MASTER-Net observations report
  3. EP260924a: Global MASTER-Net observations report
  4. GRB 260925A: Swift-BAT refined analysis
  5. GRB 260924A: Upper limits from a neutrino search with IceCube
  6. Fermi GRB 260926C: Global MASTER-Net observations report
  7. GRB260914A: MAO/AZT-22 optical observations
  8. Fermi GRB 260926A: Global MASTER-Net observations report
  9. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  10. GRB 260924A: COLIBRÍ optical observations
  11. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  12. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  13. GRB 260925A: Swift-XRT refined Analysis
  14. Swift Trigger 1513439 is probably not a GRB
  15. GRB 260925A: Swift/UVOT Upper Limits
  16. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  17. GRB 260923A: Glowbug gamma-ray detection
  18. GRB 260924A: Optical follow-up observations with Kinder
  19. GRB 260922A: Glowbug gamma-ray detection
  20. GRB 260925A: Enhanced Swift-XRT position
  21. GRB 260925A: COLIBRÍ optical upper limits
  22. GRB 260925A: FRAM-Auger optical limit
  23. GRB 260924A: Ondrejov D50 optical afterglow detection
  24. EP260924a: J-band upper limit with WINTER
  25. GRB 260924A: SVOM/GRM observation
  26. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  27. GRB 260925A: Swift detection of a burst
  28. GRB 260923A: Insight-HXMT/HE detection
  29. EP260924a: EP-WXT detection of an X-ray transient
  30. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  31. GRB 260924A: Swift/UVOT Detection
  32. GRB 260924A: GROWTH-India Telescope optical observations
  33. GRB 260924A: Swift-BAT refined analysis
  34. GRB 260924A: NuSTAR detection of prompt emission
  35. GRB 260924A: Swift-XRT refined Analysis
  36. GRB 260922A: NuSTAR detection of prompt emission
  37. GRB 260921A: NuSTAR detection of prompt emission
  38. GRB 260921A: SVOM/GRM observation
  39. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  40. GRB 260924A: Fermi GRB Observation
  41. GRB 260924A: AstroSat CZTI detection
  42. GRB 260920A: SVOM/GRM observation
  43. GRB 260924A: NOT optical counterpart confirmation
  44. GRB 260924A: Enhanced Swift-XRT position
  45. GRB 260924A: Swift detection of a burst
  46. Fermi GRB 260923A: Global MASTER-Net observations report
  47. EP260806a: e-MERLIN detection at 5 GHz
  48. GRB 260922A: Ondrejov D50 optical limit
  49. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  50. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  51. GRB 260922A: Swift-BAT refined analysis
  52. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  53. GRB 260922A: J-band upper limit with WINTER
  54. GRB 260922A: Swift/UVOT Upper Limits
  55. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  56. GRB 260922A: COLIBRÍ optical upper limits
  57. GRB 260922A: Swift-XRT refined Analysis
  58. GRB 260922A: Enhanced Swift-XRT position
  59. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  60. GRB 260920A: Glowbug gamma-ray detection
  61. GRB 260922A: SVOM/C-GFT optical upper limit
  62. GRB 260922A: Swift detection of a burst
  63. GRB 260921A: AstroSat CZTI detection
  64. GRB 260921A: Swift-BAT refined analysis
  65. GRB 260921A: Fermi GBM Observation
  66. EP Alert 260921.58: Global MASTER-Net observations report
  67. GRB 260917B:: SVOM/ECLAIRs refined analysis
  68. The EP-WXT trigger 01709319528 is likely a flaring star
  69. EP260920a: VLT/HAWK-I near-infrared candidate
  70. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  71. Swift GRB 260921A: Global MASTER-Net observations report
  72. GRB 260921A: Swift detection of a burst
  73. EP260920b: LCO observations
  74. EP260920b: SVOM/VT optical observation
  75. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  76. EP260920b: COLIBRÍ optical observations
  77. EP260920b: LCO optical counterpart detection
  78. EP Alert 260921.01: Global MASTER-Net observations report
  79. EP260920b: Global MASTER-Net observations report
  80. EP260920b: Einstein Probe detection of an X-ray transient
  81. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  82. EP Alert 260920.66: Global MASTER-Net observations report
  83. EP-WXT detected a brightening of HMXB LS V +44 17
  84. EP260920a: NOT early time optical upper limits
  85. EP260920a: NOT optical upper limits
  86. EP260920a: SVOM/VT optical upper limits
  87. EP260917a: Global MASTER-Net observations report
  88. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  89. EP260920a: COLIBRÍ optical upper limits
  90. EP260917b: EP-FXT non-detection and upper limit
  91. IceCube Alert 260919A: Global MASTER-Net observations report
  92. EP260920a: LCO optical counterpart candidate
  93. EP260920a: Einstein Probe detection of an X-ray transient
  94. EP Alert 260919.40: Global MASTER-Net observations report
  95. GRB 260915A: VLT optical and near-infrared upper limits
  96. EP260917a: SVOM/VT optical upper limits
  97. GRB 260918A: SVOM/C-GFT optical upper limits
  98. EP Alert 260918.62: Global MASTER-Net observations report
  99. Fermi GBM Sub-Threshold Detection of GRB 260918A
  100. EP Alert 260918.24: Global MASTER-Net observations report

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