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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"

12091 results found.

  1. GRB 260924A: Swift/UVOT UV grism spectrum results
  2. Fermi GRB 260926C: Global MASTER-Net observations report
  3. Fermi GRB 260926A: Global MASTER-Net observations report
  4. GRB 260926A: Fermi GBM Final Real-time Localization
  5. GRB 260924A: COLIBRÍ optical observations
  6. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  7. GRB 260925A: Swift-XRT refined Analysis
  8. Swift Trigger 1513439 is probably not a GRB
  9. Konus-Wind detection of GRB 260924A
  10. GRB 260924A: Optical follow-up observations with Kinder
  11. GRB 260925A: COLIBRÍ optical upper limits
  12. EP260924a: J-band upper limit with WINTER
  13. GRB 260925A: Swift detection of a burst
  14. GRB 260924A: Swift-XRT refined Analysis
  15. Konus-Wind detection of GRB 260922A
  16. Konus-Wind detection of GRB 260921A (possible merger-origin)
  17. GRB 260924A: Fermi-LAT detection of a bright burst
  18. GRB 260924A: AstroSat CZTI detection
  19. GRB 260924A: Swift detection of a burst
  20. Fermi GRB 260923A: Global MASTER-Net observations report
  21. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  22. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  23. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  24. GRB 260922A: Swift-XRT refined Analysis
  25. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  26. Konus-Wind detection of GRB 260810A
  27. GRB 260920A: Glowbug gamma-ray detection
  28. GRB 260922A: Swift detection of a burst
  29. GRB 260921A: AstroSat CZTI detection
  30. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  31. EP Alert 260921.58: Global MASTER-Net observations report
  32. EP260920a: VLT/HAWK-I near-infrared candidate
  33. Swift GRB 260921A: Global MASTER-Net observations report
  34. GRB 260920A: AstroSat CZTI detection
  35. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  36. EP Alert 260921.01: Global MASTER-Net observations report
  37. EP260920b: Einstein Probe detection of an X-ray transient
  38. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  39. EP Alert 260920.66: Global MASTER-Net observations report
  40. EP-WXT detected a brightening of HMXB LS V +44 17
  41. EP260920a: NOT early time optical upper limits
  42. EP260920a: NOT optical upper limits
  43. GRB 260920A: Fermi GBM Final Real-time Localization
  44. EP260917a: Global MASTER-Net observations report
  45. EP260920a: COLIBRÍ optical upper limits
  46. IceCube Alert 260919A: Global MASTER-Net observations report
  47. EP260920a: Einstein Probe detection of an X-ray transient
  48. Konus-Wind detection of GRB 260916B (short/hard)
  49. GRB 260918A: EP-FXT follow-up observation
  50. EP Alert 260917.32: Global MASTER-Net observations report
  51. Fermi trigger No 811304653: Global MASTER-Net observations report
  52. GRB 260914A: SVOM/ECLAIRs refined analysis
  53. GRB 260916A: MAXI/GSC detection
  54. MAXI GRB260916.37: Global MASTER-Net observations report
  55. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  56. GRB 260915A: 10.4m GTC deep optical limits
  57. EP Alert 260914.53: Global MASTER-Net observations report
  58. SVOM GRB260914.47: Global MASTER-Net observations report
  59. GRB 260914A: SVOM detection of a burst
  60. GRB 260818A: Continued ATCA observations
  61. GRB 260909A: OHP/T193 z-band upper limit
  62. GRB 260909A: VLT optical and near-infrared upper limits
  63. EP Alert 260909.53: Global MASTER-Net observations report
  64. GRB 260909A: SVOM/GRM observation
  65. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  66. The EP-WXT trigger 01709305715 is likely a flaring star
  67. EP260903a: EP-FXT follow-up observation
  68. GRB 260903A: SVOM/ECLAIRs refined analysis
  69. EP260903a: EP-WXT detection of a fast X-ray transient
  70. EP Alert 260903.62: Global MASTER-Net observations report
  71. SVOM GRB260903A: Global MASTER-Net observations report
  72. GRB 260903A: SVOM detection of a soft faint burst
  73. Konus-Wind detection of GRB 260829A
  74. GRB 260818A: ATCA detection of a candidate radio counterpart
  75. EP260901a: Global MASTER-Net observations report
  76. GRB 260829A: AstroSat CZTI detection
  77. EP260830a: EP-WXT detection of a fast X-ray transient
  78. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  79. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  80. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  81. EP260822a: Global MASTER-Net observations report
  82. EP Alert 260820.31: Global MASTER-Net observations report
  83. IceCube Alert 260825A: Global MASTER-Net observations report
  84. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  85. GRB 260822A: LCO optical upper limits
  86. GRB260822B: Fermi GBM Final Localization
  87. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  88. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  89. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  90. GRB 260818B: VLA radio observations
  91. EP detected a brightening of LMXB 1ES 1735-26.9
  92. GRB260820A: Fermi GBM Final Real-Time Localization
  93. GRB 260818B: SVOM/ECLAIRs refined analysis
  94. EP260806a: SAO RAS multicolor optical observations
  95. EP260806a: SVOM/ECLAIRs detection through targeted search
  96. EP260812b: Optical upper limit with Kinder
  97. EP260812a: NOT and Liverpool Telescope upper limits:
  98. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  99. EP260812b: Einstein Probe detection of an X-ray transient
  100. EP trigger #01709278129 (EP260812b?): NOT optical counterpart

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