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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"

6668 results found.

  1. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  2. GRB 231020A: Fermi GBM Detection
  3. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  4. GRB231017A: GROWTH-India upper limits on the optical afterglow
  5. GRB 231018A: Fermi GBM Detection
  6. GRB 231017A: Fermi GBM Detection
  7. GRB 231017A: Swift-XRT observations
  8. Fermi-LAT gamma-ray observations of IceCube-231014A
  9. IceCube-231004A: No significant detection in HAWC
  10. Fermi-LAT gamma-ray observations of IceCube-231004A
  11. Fermi GBM Statement for Trigger 716527670/230916144
  12. AT 2023sva: NOT observations of the ZTF candidate afterglow
  13. GRB 230915A: Fermi GBM observation
  14. GRB 230911A: Fermi GBM Observation
  15. Fermi-LAT gamma-ray observations of IceCube-230914A
  16. GRB 230906A: optical counterpart
  17. GRB 230911A: Swift-XRT afterglow detection
  18. GRB 230913A: Fermi GBM Observation
  19. GRB 230911C: Swift-XRT refined Analysis
  20. GRB 230906A: Chandra detection of the X-ray afterglow
  21. GRB 230911D: Fermi GBM observation
  22. GRB 230911D: Fermi-LAT detection
  23. GRB 230906A: BlackGEM upper limits
  24. GRB 230906A: Swift/UVOT Upper Limits
  25. GRB 230906A: Swift-XRT observations
  26. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  27. GRB 230903A: Swift-XRT refined Analysis
  28. GRB 230903A: Fermi GBM detection
  29. GRB 230827B: Swift-XRT afterglow detection
  30. GRB 230827A: Fermi GBM Observation
  31. GRB 230827B / GRB 230827256: Fermi GBM Observation
  32. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  33. GRB 230826A: Fermi GBM Observation
  34. GRB 230826A: Swift-XRT refined Analysis
  35. GRB 230822A: Fermi GBM Observation
  36. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  37. GRB 20230818A: GIT optical upper limit
  38. Konus-Wind detection of GRB 230818A
  39. GRB 230818A: Fermi GBM Observation
  40. GRB 230812B: GIT Confirmation of SN rise
  41. GRB 230812B: SAO RAS Zeiss-1000 observations
  42. GRB 230818A: further SAO RAS Zeiss-1000 observations
  43. GRB 230818A: Swift-XRT refined Analysis
  44. GRB 230818A: SAO RAS Zeiss-1000 observations
  45. Fermi GRB 230818A: Global MASTER-Net observations report
  46. Fermi trigger No 713974668: Global MASTER-Net observations report
  47. GRB 230812B: SAO RAS observations, possible re-brightening
  48. GRB 230812B: SAO RAS optical observations
  49. GRB 230816A: Swift-XRT refined Analysis
  50. GRB 230812B: optical photometry from Konkoly
  51. GRB 230812B: SAO RAS optical observations
  52. GRB230816A: Possible host and GIT detection of optical counterpart
  53. GRB 230816A: SAO RAS optical observations
  54. GRB 230815A: Swift-XRT refined Analysis
  55. GRB 230812B: iTelescope optical upper limit
  56. GRB 230812B: continued SAO RAS optical observation
  57. GRB 230815A: Fermi GBM detection
  58. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  59. GRB 230812B: further SAO RAS optical observations
  60. GRB 230812B: Upper limits from a neutrino search with IceCube
  61. GRB 230812B: GIT optical follow-up
  62. GRB 230812B: rest-frame energetics from Konus-Wind observation
  63. GRB 230812B: SAO RAS optical observations
  64. GRB 230812B: Swift-XRT afterglow detection
  65. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  66. GRB 230812B: Improved Swift/XRT localization
  67. GRB 230812B: Fermi-LAT detection
  68. GRB 230808A: Fermi GBM Detection
  69. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  70. GRB 230805B: Fermi GBM observation
  71. GRB 230805B: Swift-XRT refined Analysis
  72. GRB 230805B: SAO RAS optical observations
  73. GRB 230802A: Fermi GBM observation
  74. GRB 230802A: Swift-XRT refined Analysis
  75. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  76. Fermi-LAT gamma-ray observations of IceCube-230727A
  77. GRB 230728A: Fermi GBM Observation
  78. GRB 230728A: Swift-XRT refined Analysis
  79. Fermi-LAT gamma-ray observations of IceCube-230725A
  80. Fermi-LAT gamma-ray observations of IceCube-230724A
  81. GRB 230723B: Fermi GBM observation
  82. GRB 230723B: Swift-XRT refined Analysis
  83. Swift-XRT position for GRB 230723B
  84. GRB 230709C: Fermi GBM Detection
  85. GRB 230707B: Fermi GBM Observation
  86. IceCube-230707A: No candidates detected by Swift-XRT
  87. Fermi-LAT gamma-ray observations of IceCube-230708A
  88. Fermi-LAT gamma-ray observations of IceCube-230707B
  89. Fermi-LAT gamma-ray observations of IceCube-230707A
  90. GRB 230707A: Swift-XRT observations
  91. GRB 230707A: Fermi GBM Detection
  92. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  93. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  94. GRB 230628E: Swift-XRT refined Analysis
  95. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  96. GRB230626A: Fermi GBM Detection
  97. GRB 230623A: Swift-XRT observations
  98. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  99. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  100. GRB 230622A: Swift-XRT refined Analysis

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