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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"

41622 results found.

  1. GRB 260924A: Upper limits from a neutrino search with IceCube
  2. Fermi GRB 260926C: Global MASTER-Net observations report
  3. GRB 260926C: Fermi GBM Final Real-time Localization
  4. GRB260914A: MAO/AZT-22 optical observations
  5. GRB 260926B: Fermi GBM Final Real-time Localization
  6. Fermi GRB 260926A: Global MASTER-Net observations report
  7. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  8. GRB 260926A: Fermi GBM Final Real-time Localization
  9. The EP-WXT trigger 01709320726 is likely a flaring star
  10. GRB 260924A: COLIBRÍ optical observations
  11. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  12. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  13. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  14. GRB 260925A: Swift-XRT refined Analysis
  15. EP260924a: EP-FXT follow-up observation
  16. Swift Trigger 1513439 is probably not a GRB
  17. GRB 260925A: Swift/UVOT Upper Limits
  18. Konus-Wind detection of GRB 260924A
  19. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  20. GRB 260923A: Glowbug gamma-ray detection
  21. GRB 260924A: Optical follow-up observations with Kinder
  22. GRB 260922A: Glowbug gamma-ray detection
  23. GRB 260925A: Enhanced Swift-XRT position
  24. GRB 260925A: COLIBRÍ optical upper limits
  25. GRB 260925A: FRAM-Auger optical limit
  26. GRB 260924A: Ondrejov D50 optical afterglow detection
  27. EP260924a: J-band upper limit with WINTER
  28. GRB 260924A: SVOM/GRM observation
  29. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  30. GRB 260925A: Swift detection of a burst
  31. GRB 260923A: Insight-HXMT/HE detection
  32. EP260924a: EP-WXT detection of an X-ray transient
  33. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  34. GRB 260924A: Swift/UVOT Detection
  35. GRB 260924A: GROWTH-India Telescope optical observations
  36. GRB 260924A: Swift-BAT refined analysis
  37. GRB 260924A: NuSTAR detection of prompt emission
  38. GRB 260924A: Swift-XRT refined Analysis
  39. Konus-Wind detection of GRB 260922A
  40. GRB 260922A: NuSTAR detection of prompt emission
  41. GRB 260921A: NuSTAR detection of prompt emission
  42. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  43. GRB 260921A: SVOM/GRM observation
  44. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  45. GRB 260924A: Fermi GRB Observation
  46. Konus-Wind detection of GRB 260921A (possible merger-origin)
  47. GRB 260924A: Fermi-LAT detection of a bright burst
  48. GRB 260924A: AstroSat CZTI detection
  49. GRB 260920A: SVOM/GRM observation
  50. GRB 260924A: NOT optical counterpart confirmation
  51. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  52. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  53. GRB 260924A: Enhanced Swift-XRT position
  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. Trigger_21914: Swift ToO observations
  60. EP260806a: e-MERLIN detection at 5 GHz
  61. GRB 260922A: Ondrejov D50 optical limit
  62. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  63. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  64. ATCA observations of GRB 260909A
  65. GRB 260922A: Swift-BAT refined analysis
  66. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  67. GRB 260922A: J-band upper limit with WINTER
  68. GRB 260922A: Swift/UVOT Upper Limits
  69. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  70. GRB 260922A: COLIBRÍ optical upper limits
  71. GRB 260922A: Swift-XRT refined Analysis
  72. GRB 260922A: Enhanced Swift-XRT position
  73. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  74. Konus-Wind detection of GRB 260810A
  75. GRB 260920A: Glowbug gamma-ray detection
  76. GRB 260918A: SVOM/ECLAIRs refined analysis
  77. GRB 260922A: SVOM/C-GFT optical upper limit
  78. GRB 260922A: Swift detection of a burst
  79. GRB 260917C: AstroSat CZTI detection
  80. GRB 260920B/EP260920b: GECAM-B detection of a burst
  81. GRB 260921A: AstroSat CZTI detection
  82. GRB 260921A: Swift-BAT refined analysis
  83. GRB 260921B: Fermi GBM Final Localization
  84. GRB 260921A: Fermi GBM Observation
  85. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  86. EP Alert 260921.58: Global MASTER-Net observations report
  87. GRB 260917B:: SVOM/ECLAIRs refined analysis
  88. The EP-WXT trigger 01709319528 is likely a flaring star
  89. EP260920a: VLT/HAWK-I near-infrared candidate
  90. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  91. Swift GRB 260921A: Global MASTER-Net observations report
  92. GRB 260921A: Swift detection of a burst
  93. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  94. GRB 260921A: Fermi GBM Final Real-time Localization
  95. EP260920b: LCO observations
  96. GRB 260920A: AstroSat CZTI detection
  97. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  98. EP260920b: COLIBRÍ optical observations
  99. EP260920b: LCO optical counterpart detection
  100. The EP-WXT trigger 01709318601 is likely a flaring star

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