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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"

11749 results found.

  1. Konus-Wind detection of GRB 260924A
  2. GRB 260924A: Optical follow-up observations with Kinder
  3. GRB 260925A: COLIBRÍ optical upper limits
  4. EP260924a: J-band upper limit with WINTER
  5. GRB 260925A: Swift detection of a burst
  6. GRB 260924A: Swift-XRT refined Analysis
  7. Konus-Wind detection of GRB 260922A
  8. Konus-Wind detection of GRB 260921A (possible merger-origin)
  9. GRB 260924A: Fermi-LAT detection of a bright burst
  10. GRB 260924A: AstroSat CZTI detection
  11. GRB 260924A: Swift detection of a burst
  12. Fermi GRB 260923A: Global MASTER-Net observations report
  13. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  14. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  15. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  16. GRB 260922A: Swift-XRT refined Analysis
  17. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  18. Konus-Wind detection of GRB 260810A
  19. GRB 260920A: Glowbug gamma-ray detection
  20. GRB 260922A: Swift detection of a burst
  21. GRB 260921A: AstroSat CZTI detection
  22. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  23. EP Alert 260921.58: Global MASTER-Net observations report
  24. EP260920a: VLT/HAWK-I near-infrared candidate
  25. Swift GRB 260921A: Global MASTER-Net observations report
  26. GRB 260920A: AstroSat CZTI detection
  27. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  28. EP Alert 260921.01: Global MASTER-Net observations report
  29. EP260920b: Einstein Probe detection of an X-ray transient
  30. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  31. EP Alert 260920.66: Global MASTER-Net observations report
  32. EP-WXT detected a brightening of HMXB LS V +44 17
  33. EP260920a: NOT early time optical upper limits
  34. EP260920a: NOT optical upper limits
  35. GRB 260920A: Fermi GBM Final Real-time Localization
  36. EP260917a: Global MASTER-Net observations report
  37. EP260920a: COLIBRÍ optical upper limits
  38. IceCube Alert 260919A: Global MASTER-Net observations report
  39. EP260920a: Einstein Probe detection of an X-ray transient
  40. Konus-Wind detection of GRB 260916B (short/hard)
  41. GRB 260918A: EP-FXT follow-up observation
  42. EP Alert 260917.32: Global MASTER-Net observations report
  43. Fermi trigger No 811304653: Global MASTER-Net observations report
  44. GRB 260914A: SVOM/ECLAIRs refined analysis
  45. GRB 260916A: MAXI/GSC detection
  46. MAXI GRB260916.37: Global MASTER-Net observations report
  47. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  48. GRB 260915A: 10.4m GTC deep optical limits
  49. EP Alert 260914.53: Global MASTER-Net observations report
  50. SVOM GRB260914.47: Global MASTER-Net observations report
  51. GRB 260914A: SVOM detection of a burst
  52. GRB 260818A: Continued ATCA observations
  53. GRB 260909A: OHP/T193 z-band upper limit
  54. GRB 260909A: VLT optical and near-infrared upper limits
  55. EP Alert 260909.53: Global MASTER-Net observations report
  56. GRB 260909A: SVOM/GRM observation
  57. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  58. The EP-WXT trigger 01709305715 is likely a flaring star
  59. EP260903a: EP-FXT follow-up observation
  60. GRB 260903A: SVOM/ECLAIRs refined analysis
  61. EP260903a: EP-WXT detection of a fast X-ray transient
  62. EP Alert 260903.62: Global MASTER-Net observations report
  63. SVOM GRB260903A: Global MASTER-Net observations report
  64. GRB 260903A: SVOM detection of a soft faint burst
  65. Konus-Wind detection of GRB 260829A
  66. GRB 260818A: ATCA detection of a candidate radio counterpart
  67. EP260901a: Global MASTER-Net observations report
  68. GRB 260829A: AstroSat CZTI detection
  69. EP260830a: EP-WXT detection of a fast X-ray transient
  70. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  71. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  72. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  73. EP260822a: Global MASTER-Net observations report
  74. EP Alert 260820.31: Global MASTER-Net observations report
  75. IceCube Alert 260825A: Global MASTER-Net observations report
  76. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  77. GRB 260822A: LCO optical upper limits
  78. GRB260822B: Fermi GBM Final Localization
  79. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  80. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  81. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  82. GRB 260818B: VLA radio observations
  83. EP detected a brightening of LMXB 1ES 1735-26.9
  84. GRB260820A: Fermi GBM Final Real-Time Localization
  85. GRB 260818B: SVOM/ECLAIRs refined analysis
  86. EP260806a: SAO RAS multicolor optical observations
  87. EP260806a: SVOM/ECLAIRs detection through targeted search
  88. EP260812b: Optical upper limit with Kinder
  89. EP260812a: NOT and Liverpool Telescope upper limits:
  90. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  91. EP260812b: Einstein Probe detection of an X-ray transient
  92. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  93. GRB 260810A: AstroSat CZTI detection of a long burst
  94. EP260812a: Einstein Probe detection of an X-ray transient
  95. GRB 260809A: SAO RAS optical observations
  96. GRB 260807A: SVOM/ECLAIRs refined analysis
  97. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  98. GRB 260808B: SVOM/ECLAIRs refined analysis
  99. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  100. GRB 260808B: LCO optical observations

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