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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"

22056 results found.

  1. EP240801a: GSP follow-up observations of the candidate counterpart
  2. Fermi trigger No 744204856: Global MASTER-Net observations report
  3. EP240801a: Kinder follow-up observations of the candidate counterpart
  4. EP240708a: Kinder follow-up observations of the candidate counterpart (duplicate submission of GCN 37002)
  5. EP240801a: KAIT optical counterpart observations
  6. EP240801a: TRT optical counterpart detection
  7. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  8. Fermi GRB 240801A: Global MASTER-Net observations report
  9. Fermi trigger No 744128417: Global MASTER-Net observations report
  10. Fermi trigger No 744083370: Global MASTER-Net observations report
  11. GRB 240730A: Osservatorio Astronomico Nastro Verde upper limit
  12. Fermi GRB 240730B: Global MASTER-Net observations report
  13. Swift GRB 240730A: Global MASTER-Net observations report
  14. GRB 240715A: Swift-XRT afterglow detection
  15. GRB 240730A: Swift/UVOT Upper Limits
  16. GRB 240730A: Swift detection of a burst
  17. Fermi trigger No 743953682: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
  19. GRB 240727A: observations of optical counterpart.
  20. GRB 240727B: Swift-XRT observations
  21. Fermi GRB 240727A: Global MASTER-Net observations report
  22. GRB 240727A: Swift/UVOT detection
  23. Fermi trigger No 743868421: Global MASTER-Net observations report
  24. GRB 240727A: Osservatorio Astronomico Nastro Verde upper limit
  25. GRB 240727A: JinShan optical upper limits
  26. GRB 240727A Bassano Bresciano Observatory upper limit
  27. Fermi GRB 240726A: Global MASTER-Net observations report
  28. Swift GRB240727.16: Global MASTER-Net observations report
  29. GRB 240727B: Swift ToO observations
  30. GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
  31. GRB240727A: Skynet Optical Afterglow Observations
  32. GRB 240727A: TRT optical afterglow detection
  33. GRB 240727A: KAIT Optical Afterglow Candidate
  34. Fermi-LAT gamma-ray observations of IceCube-240725A
  35. IceCube Alert 240725.22: Global MASTER-Net observations report
  36. Swift GRB240725.11: Global MASTER-Net observations report
  37. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  38. Fermi trigger No 743418632: Global MASTER-Net observations report
  39. Fermi trigger No 743315411: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
  41. LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
  42. Fermi trigger No 743345551: Global MASTER-Net observations report
  43. Fermi-LAT gamma-ray observations of IceCube-240721A
  44. Fermi trigger No 743219692: Global MASTER-Net observations report
  45. IceCube Alert 240721.68: Global MASTER-Net observations report
  46. Fermi GRB 240720A: Global MASTER-Net observations report
  47. Swift GRB240720.02: Global MASTER-Net observations report
  48. Konus-Wind detection of GRB 240718A
  49. Fermi GRB 240718A: Global MASTER-Net observations report
  50. LAT GRB240718.27: Global MASTER-Net observations report
  51. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  52. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  53. GRB 240715A: Swift/UVOT observations of the XRT sources.
  54. GRB 240715A: Swift-XRT observations
  55. GRB240713A: Swift/UVOT Upper LImits
  56. EP240708a: X-ray follow-up observations with Swift/XRT
  57. GRB 240713A: Swift-XRT observations
  58. GRB 240713A: LAST optical upper limit
  59. GRB 240715A: Swift ToO observations
  60. Fermi GRB 240715A: Global MASTER-Net observations report
  61. GRB 240712A ATCA radio observations
  62. GRB240715A: GRANDMA Optical Upper Limits
  63. GRB 240712A: Swift/UVOT Upper Limits
  64. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  65. The EP-WXT source triggered on July 14th is likely a flaring star
  66. GRB 240713A: Tiled Swift observations
  67. GRB 240713A: J-band upper limit from WINTER
  68. GRB 240713A: JinShan optical upper limits
  69. GRB 240713A: OHP/T120 optical upper limit
  70. GRB240713A: Optical upper limit with Kinder observations
  71. GRB240713A: TAROT and GRANDMA Observations of SVOM/ECLAIRs GRB240713A
  72. EP240708a: GSP optical upper limit
  73. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  74. Fermi trigger No 742405878: Global MASTER-Net observations report
  75. Fermi trigger No 742317942: Global MASTER-Net observations report
  76. Fermi GRB 240710A: Global MASTER-Net observations report
  77. EP240708a: NOT optical observations
  78. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  79. EP240708a: Optical upper limits with Kinder observations
  80. EP240708a: EP-WXT detection of a fast X-ray transient
  81. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  82. EP240703b: GSP optical upper limit
  83. EP240703b: TRT optical upper limits
  84. EP240703a: TRT further optical observation
  85. EP240702a: TRT optical upper limits
  86. Konus-Wind detection of GRB 240627A
  87. EP240703a and EP240703b: Swift/XRT upper limits
  88. EP240703a: BTA observations
  89. EP240703c: Kinder optical follow-up and Swift XRT observations
  90. EP240703a: Liverpool Telescope optical follow-up observations
  91. EP240703a: Kinder optical follow-up observations
  92. EP240703c: EP-WXT detection of an X-ray transient
  93. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  94. EP240703b: EP-WXT detection of a fast X-ray transient
  95. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  96. EP240703a: EP-WXT detection of a fast X-ray transient
  97. EP240702a: GSP optical upper limit
  98. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  99. Fermi GRB 240702A: Global MASTER-Net observations report
  100. EP240702a: EP-WXT detection of a fast X-ray transient

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