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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"

1094 results found.

  1. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  2. EP241026b: EP detection of a fast X-ray transient
  3. GRB 241025A: Fermi GBM Observation
  4. EP 241021a: Swift-XRT observations
  5. EP241025a (GRB 241025A): EP observations update
  6. EP 241021A: Swift ToO observations
  7. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  8. EP241021a: EP-FXT follow-up observation update
  9. EP241021a: 1.3m DFOT Optical observations
  10. EP241021a: TRT optical observations
  11. EP241021a: NOT likely optical counterpart
  12. GRB 241018A: EP-FXT afterglow detection
  13. EP241021a: EP detection of a fast X-ray transient
  14. GRB 241001A: EP-FXT afterglow detection
  15. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  16. GRB 240930B: Fermi GBM Observation
  17. EP240930a: EP-FXT follow-up observation update
  18. EP240930a: EP-WXT detection of a fast X-ray transient
  19. EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
  20. EP240918b and EP240918c: EP-FXT follow-up observations
  21. EP trigger ID 01709059262: the X-ray transient is likely a stellar flare event
  22. EP240919a: EP-FXT follow-up observation update
  23. Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
  24. EP240919a is likely a GRB event
  25. EP240919a: EP-WXT detection of a fast X-ray transient
  26. EP240918b and EP240918c: EP-WXT detection of two fast X-ray transients
  27. EP240918a: EP observation update
  28. EP240918a: Swift-XRT observation
  29. EP240918a: YAHPT Optical Upper Limit
  30. EP240918a: Optical upper limits with Kinder observations
  31. EP240918a: an X-ray transient detected by Einstein Probe
  32. The EP-WXT triggers 01709047257 and 01709047278 are not real sources
  33. EP240913a: VLT/HAWK-I near-infrared upper limits
  34. GRB 240913C: Fermi GBM detection
  35. EP240913a: NOT optical upper limits
  36. EP240913a: JinShan optical upper limits
  37. EP240913a: A GRB Event
  38. EP240913a: EP-WXT detection of a fast X-ray transient
  39. EP240908a: Updates on the WXT detection result around the trigger time
  40. EP240908a: EP detection of a fast X-ray transient
  41. SVOM GRB 240821A: optical afterglow discovery
  42. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  43. EP240820a: PRIME J-band Observations
  44. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  45. EP240820a: EP detection of a fast X-ray transient
  46. EP240816a: PRIME upper limits
  47. GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
  48. GRB 240819A: X-ray follow-up observation with EP-FXT
  49. EP240816b: KAIT optical upper limit
  50. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  51. EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  52. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  53. EP240807a: PRIME H-band upper limits
  54. X-ray Transient EP240807a: PRIME near-infrared upper limits
  55. EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
  56. EP240807a: STEP/T80S optical limits
  57. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  58. EP-WXT trigger 01709018832: KAIT optical observations of the star flare
  59. EP240802a/GRB240802A: KAIT optical upper limit
  60. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  61. EP240807a: EP-WXT detection of a fast X-ray transient
  62. EP240806a: KAIT optical observations
  63. EP240806a: LCOGT optical counterpart detection
  64. EP240806a: EP-FXT detection of the X-ray emission
  65. EP240806a: EP-WXT detection of a fast X-ray transient
  66. EP240804a: VLT/X-shooter spectroscopic redshift
  67. EP240804a: LCOGT optical counterpart detection
  68. EP-WXT trigger 00109017646 is not a real source
  69. EP240804a: NOT optical counterpart detection
  70. EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  71. EP240802a: correction of EP-WXT trigger time in GCN 37019
  72. EP240802a: Montarrenti Observatory optical upper limit
  73. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  74. EP240802A: Bassano Bresciano Observatory upper limit
  75. EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  76. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  77. EP240801a: Leavitt Observatory optical observations
  78. EP240801a: NOT optical observations
  79. EP240801a: follow-up observation with LCOGT
  80. EP240801a: GSP follow-up observations of the candidate counterpart
  81. EP240801a: KAIT optical counterpart observations
  82. EP240801a: TRT optical counterpart detection
  83. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  84. EP-WXT trigger 01709002661 is not a real source
  85. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  86. EP240708a: X-ray follow-up observations with Swift/XRT
  87. EP-WXT flaring star and the optical flaring activity during its decay phase
  88. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  89. The EP-WXT source triggered on July 14th is likely a flaring star
  90. GRB240713A: X-ray follow-up observation with EP-FXT
  91. EP240708a: GSP optical upper limit
  92. EP240708a: KAIT optical upper limit
  93. EP240708a: SVOM/C-GFT optical upper limit
  94. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  95. EP240708a: EP-WXT detection of a fast X-ray transient
  96. EP240703b: GSP optical upper limit
  97. EP240703a and EP240703b: Swift/XRT upper limits
  98. EP240703a: KAIT optical upper limit
  99. EP240703c: EP-WXT detection of an X-ray transient
  100. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT

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