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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"

6797 results found.

  1. GRB 230805B: SAO RAS optical observations
  2. GRB 230802A: Fermi GBM observation
  3. GRB 230802A: Swift-XRT refined Analysis
  4. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  5. Fermi-LAT gamma-ray observations of IceCube-230727A
  6. GRB 230728A: Fermi GBM Observation
  7. GRB 230728A: Swift-XRT refined Analysis
  8. Fermi-LAT gamma-ray observations of IceCube-230725A
  9. Fermi-LAT gamma-ray observations of IceCube-230724A
  10. GRB 230723B: Fermi GBM observation
  11. GRB 230723B: Swift-XRT refined Analysis
  12. Swift-XRT position for GRB 230723B
  13. GRB 230709C: Fermi GBM Detection
  14. GRB 230707B: Fermi GBM Observation
  15. IceCube-230707A: No candidates detected by Swift-XRT
  16. Fermi-LAT gamma-ray observations of IceCube-230708A
  17. Fermi-LAT gamma-ray observations of IceCube-230707B
  18. Fermi-LAT gamma-ray observations of IceCube-230707A
  19. GRB 230707A: Swift-XRT observations
  20. GRB 230707A: Fermi GBM Detection
  21. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  22. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  23. GRB 230628E: Swift-XRT refined Analysis
  24. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  25. GRB230626A: Fermi GBM Detection
  26. GRB 230623A: Swift-XRT observations
  27. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  28. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  29. GRB 230622A: Swift-XRT refined Analysis
  30. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  31. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  32. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
  33. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  34. GRB 230618A: Swift-XRT refined Analysis
  35. GRB 230616A: Swift-XRT observations
  36. LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
  37. GRB 230614B: Fermi GBM Observation
  38. GRB 230614C: Fermi GBM Detection
  39. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  40. GRB 230506B: Chandra localization of the X-ray afterglow
  41. GRB 230606A: Fermi GBM Observation
  42. GRB 230606A: Swift-XRT refined Analysis
  43. Fermi-LAT gamma-ray observations of IceCube-230603A
  44. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  45. Alert from the HAWC Burst Monitor HAWC-230527A
  46. Fermi-LAT gamma-ray observations of IceCube-230524A
  47. GRB 230525A: Fermi GBM Detection
  48. GRB 230524A: Fermi GBM Observation
  49. GRB 230518A: Fermi GBM Observation
  50. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  51. LIGO/Virgo S230518h: AGILE/MCAL observations
  52. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  53. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  54. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  55. GRB 230510B: Fermi GBM detection
  56. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  57. Fermi-LAT gamma-ray observations of IceCube-230511A
  58. GRB 230512A: Swift-XRT observations
  59. GRB 230512A: GIT optical follow-up ZTF candidates
  60. GRB 230512A: Fermi GBM detection
  61. GRB 230512A: Fermi-LAT detection
  62. GRB 230510A: GIT optical upper limits
  63. GRB 230510A: Fermi GBM detection
  64. GRB 230506B: Fermi GBM detection
  65. GRB 230510A: Swift-XRT refined Analysis
  66. GRB 230506C: Fermi GBM detection
  67. GRB 230506C: SAO RAS optical observations
  68. Fermi-LAT gamma-ray observations of IceCube-230506A
  69. GRB 230506C: Swift-XRT refined Analysis
  70. GRB 230506C: Swift/UVOT Upper Limits
  71. GRB 230506B: Swift-XRT refined Analysis
  72. GRB 230506C: Swift-XRT analysis
  73. GRB 230430A: Fermi GBM observation
  74. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  75. GRB 230427A: Swift-XRT refined Analysis
  76. GRB 230427A: GIT optical upper limit
  77. GRB 230426A: Fermi GBM Detection
  78. GRB 230423A: Swift-XRT refined Analysis
  79. GRB 230421A: Fermi GBM observation
  80. GRB 230420A: Swift-XRT refined Analysis
  81. GRB 230420A: NOT optical afterglow confirmation
  82. GRB 230402A: Fermi GBM detection
  83. GRB 230418A: Fermi GBM Observation
  84. GRB 230402A: Fermi-LAT detection
  85. Fermi-LAT gamma-ray observations of IceCube-230416A
  86. GRB 230415A: Fermi GBM detection
  87. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  88. GRB 230307A: iTelescope optical upper limit (likely)
  89. GRB 230414B: Lulin 40cm-SLT optical limit
  90. GRB 230414B: Swift-XRT refined Analysis
  91. GRB 230414B: 1.3m DFOT Optical observations
  92. GRB 230328B: redshift lower limit estimating
  93. GRB 230409B: Swift-XRT refined Analysis
  94. Fermi-LAT gamma-ray observations of IceCube-230405A
  95. GRB 230405B: Swift-XRT refined Analysis
  96. GRB 230405B: Fermi GBM Observation
  97. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  98. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  99. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  100. GRB 230328B: 3.6m DOT multiband optical observation

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