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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"

6519 results found.

  1. GRB 230812B: optical photometry from Konkoly
  2. GRB 230812B: SAO RAS optical observations
  3. GRB230816A: Possible host and GIT detection of optical counterpart
  4. GRB 230816A: SAO RAS optical observations
  5. GRB 230815A: Swift-XRT refined Analysis
  6. GRB 230812B: iTelescope optical upper limit
  7. GRB 230812B: continued SAO RAS optical observation
  8. GRB 230815A: Fermi GBM detection
  9. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  10. GRB 230812B: further SAO RAS optical observations
  11. GRB 230812B: Upper limits from a neutrino search with IceCube
  12. GRB 230812B: GIT optical follow-up
  13. GRB 230812B: rest-frame energetics from Konus-Wind observation
  14. GRB 230812B: SAO RAS optical observations
  15. GRB 230812B: Swift-XRT afterglow detection
  16. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  17. GRB 230812B: Improved Swift/XRT localization
  18. GRB 230812B: Fermi-LAT detection
  19. GRB 230808A: Fermi GBM Detection
  20. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  21. GRB 230805B: Fermi GBM observation
  22. GRB 230805B: Swift-XRT refined Analysis
  23. GRB 230805B: SAO RAS optical observations
  24. GRB 230802A: Fermi GBM observation
  25. GRB 230802A: Swift-XRT refined Analysis
  26. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  27. Fermi-LAT gamma-ray observations of IceCube-230727A
  28. GRB 230728A: Fermi GBM Observation
  29. GRB 230728A: Swift-XRT refined Analysis
  30. Fermi-LAT gamma-ray observations of IceCube-230725A
  31. Fermi-LAT gamma-ray observations of IceCube-230724A
  32. GRB 230723B: Fermi GBM observation
  33. GRB 230723B: Swift-XRT refined Analysis
  34. Swift-XRT position for GRB 230723B
  35. GRB 230709C: Fermi GBM Detection
  36. GRB 230707B: Fermi GBM Observation
  37. IceCube-230707A: No candidates detected by Swift-XRT
  38. Fermi-LAT gamma-ray observations of IceCube-230708A
  39. Fermi-LAT gamma-ray observations of IceCube-230707B
  40. Fermi-LAT gamma-ray observations of IceCube-230707A
  41. GRB 230707A: Swift-XRT observations
  42. GRB 230707A: Fermi GBM Detection
  43. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  44. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  45. GRB 230628E: Swift-XRT refined Analysis
  46. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  47. GRB230626A: Fermi GBM Detection
  48. GRB 230623A: Swift-XRT observations
  49. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  50. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  51. GRB 230622A: Swift-XRT refined Analysis
  52. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  53. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  54. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
  55. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  56. GRB 230618A: Swift-XRT refined Analysis
  57. GRB 230616A: Swift-XRT observations
  58. LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
  59. GRB 230614B: Fermi GBM Observation
  60. GRB 230614C: Fermi GBM Detection
  61. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  62. GRB 230506B: Chandra localization of the X-ray afterglow
  63. GRB 230606A: Fermi GBM Observation
  64. GRB 230606A: Swift-XRT refined Analysis
  65. Fermi-LAT gamma-ray observations of IceCube-230603A
  66. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  67. Alert from the HAWC Burst Monitor HAWC-230527A
  68. Fermi-LAT gamma-ray observations of IceCube-230524A
  69. GRB 230525A: Fermi GBM Detection
  70. GRB 230524A: Fermi GBM Observation
  71. GRB 230518A: Fermi GBM Observation
  72. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  73. LIGO/Virgo S230518h: AGILE/MCAL observations
  74. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  75. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  76. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  77. GRB 230510B: Fermi GBM detection
  78. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  79. Fermi-LAT gamma-ray observations of IceCube-230511A
  80. GRB 230512A: Swift-XRT observations
  81. GRB 230512A: GIT optical follow-up ZTF candidates
  82. GRB 230512A: Fermi GBM detection
  83. GRB 230512A: Fermi-LAT detection
  84. GRB 230510A: GIT optical upper limits
  85. GRB 230510A: Fermi GBM detection
  86. GRB 230506B: Fermi GBM detection
  87. GRB 230510A: Swift-XRT refined Analysis
  88. GRB 230506C: Fermi GBM detection
  89. GRB 230506C: SAO RAS optical observations
  90. Fermi-LAT gamma-ray observations of IceCube-230506A
  91. GRB 230506C: Swift-XRT refined Analysis
  92. GRB 230506C: Swift/UVOT Upper Limits
  93. GRB 230506B: Swift-XRT refined Analysis
  94. GRB 230506C: Swift-XRT analysis
  95. GRB 230430A: Fermi GBM observation
  96. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  97. GRB 230427A: Swift-XRT refined Analysis
  98. GRB 230427A: GIT optical upper limit
  99. GRB 230426A: Fermi GBM Detection
  100. GRB 230423A: Swift-XRT refined Analysis

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