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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"

6405 results found.

  1. GRB 230812B: Swift-XRT afterglow detection
  2. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  3. GRB 230812B: Improved Swift/XRT localization
  4. GRB 230812B: Fermi-LAT detection
  5. GRB 230808A: Fermi GBM Detection
  6. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  7. GRB 230805B: Fermi GBM observation
  8. GRB 230805B: Swift-XRT refined Analysis
  9. GRB 230805B: SAO RAS optical observations
  10. GRB 230802A: Fermi GBM observation
  11. GRB 230802A: Swift-XRT refined Analysis
  12. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  13. Fermi-LAT gamma-ray observations of IceCube-230727A
  14. GRB 230728A: Fermi GBM Observation
  15. GRB 230728A: Swift-XRT refined Analysis
  16. Fermi-LAT gamma-ray observations of IceCube-230725A
  17. Fermi-LAT gamma-ray observations of IceCube-230724A
  18. GRB 230723B: Fermi GBM observation
  19. GRB 230723B: Swift-XRT refined Analysis
  20. Swift-XRT position for GRB 230723B
  21. GRB 230709C: Fermi GBM Detection
  22. GRB 230707B: Fermi GBM Observation
  23. IceCube-230707A: No candidates detected by Swift-XRT
  24. Fermi-LAT gamma-ray observations of IceCube-230708A
  25. Fermi-LAT gamma-ray observations of IceCube-230707B
  26. Fermi-LAT gamma-ray observations of IceCube-230707A
  27. GRB 230707A: Swift-XRT observations
  28. GRB 230707A: Fermi GBM Detection
  29. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  30. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  31. GRB 230628E: Swift-XRT refined Analysis
  32. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  33. GRB230626A: Fermi GBM Detection
  34. GRB 230623A: Swift-XRT observations
  35. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  36. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  37. GRB 230622A: Swift-XRT refined Analysis
  38. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  39. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  40. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
  41. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  42. GRB 230618A: Swift-XRT refined Analysis
  43. GRB 230616A: Swift-XRT observations
  44. LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
  45. GRB 230614B: Fermi GBM Observation
  46. GRB 230614C: Fermi GBM Detection
  47. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  48. GRB 230506B: Chandra localization of the X-ray afterglow
  49. GRB 230606A: Fermi GBM Observation
  50. GRB 230606A: Swift-XRT refined Analysis
  51. Fermi-LAT gamma-ray observations of IceCube-230603A
  52. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  53. Alert from the HAWC Burst Monitor HAWC-230527A
  54. Fermi-LAT gamma-ray observations of IceCube-230524A
  55. GRB 230525A: Fermi GBM Detection
  56. GRB 230524A: Fermi GBM Observation
  57. GRB 230518A: Fermi GBM Observation
  58. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  59. LIGO/Virgo S230518h: AGILE/MCAL observations
  60. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  61. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  62. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  63. GRB 230510B: Fermi GBM detection
  64. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  65. Fermi-LAT gamma-ray observations of IceCube-230511A
  66. GRB 230512A: Swift-XRT observations
  67. GRB 230512A: GIT optical follow-up ZTF candidates
  68. GRB 230512A: Fermi GBM detection
  69. GRB 230512A: Fermi-LAT detection
  70. GRB 230510A: GIT optical upper limits
  71. GRB 230510A: Fermi GBM detection
  72. GRB 230506B: Fermi GBM detection
  73. GRB 230510A: Swift-XRT refined Analysis
  74. GRB 230506C: Fermi GBM detection
  75. GRB 230506C: SAO RAS optical observations
  76. Fermi-LAT gamma-ray observations of IceCube-230506A
  77. GRB 230506C: Swift-XRT refined Analysis
  78. GRB 230506C: Swift/UVOT Upper Limits
  79. GRB 230506B: Swift-XRT refined Analysis
  80. GRB 230506C: Swift-XRT analysis
  81. GRB 230430A: Fermi GBM observation
  82. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  83. GRB 230427A: Swift-XRT refined Analysis
  84. GRB 230427A: GIT optical upper limit
  85. GRB 230426A: Fermi GBM Detection
  86. GRB 230423A: Swift-XRT refined Analysis
  87. GRB 230421A: Fermi GBM observation
  88. GRB 230420A: Swift-XRT refined Analysis
  89. GRB 230420A: NOT optical afterglow confirmation
  90. GRB 230402A: Fermi GBM detection
  91. GRB 230418A: Fermi GBM Observation
  92. GRB 230402A: Fermi-LAT detection
  93. Fermi-LAT gamma-ray observations of IceCube-230416A
  94. GRB 230415A: Fermi GBM detection
  95. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  96. GRB 230307A: iTelescope optical upper limit (likely)
  97. GRB 230414B: Lulin 40cm-SLT optical limit
  98. GRB 230414B: Swift-XRT refined Analysis
  99. GRB 230414B: 1.3m DFOT Optical observations
  100. GRB 230328B: redshift lower limit estimating

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