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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"

6094 results found.

  1. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  2. Fermi-LAT gamma-ray observations of IceCube-230727A
  3. GRB 230728A: Fermi GBM Observation
  4. GRB 230728A: Swift-XRT refined Analysis
  5. Fermi-LAT gamma-ray observations of IceCube-230725A
  6. Fermi-LAT gamma-ray observations of IceCube-230724A
  7. GRB 230723B: Fermi GBM observation
  8. GRB 230723B: Swift-XRT refined Analysis
  9. Swift-XRT position for GRB 230723B
  10. GRB 230709C: Fermi GBM Detection
  11. GRB 230707B: Fermi GBM Observation
  12. IceCube-230707A: No candidates detected by Swift-XRT
  13. Fermi-LAT gamma-ray observations of IceCube-230708A
  14. Fermi-LAT gamma-ray observations of IceCube-230707B
  15. Fermi-LAT gamma-ray observations of IceCube-230707A
  16. GRB 230707A: Swift-XRT observations
  17. GRB 230707A: Fermi GBM Detection
  18. ZTF23aaoohpy/AT2023lcr : HCT follow-up observations
  19. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  20. GRB 230628E: Swift-XRT refined Analysis
  21. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  22. GRB230626A: Fermi GBM Detection
  23. GRB 230623A: Swift-XRT observations
  24. INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
  25. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  26. GRB 230622A: Swift-XRT refined Analysis
  27. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  28. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
  29. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
  30. ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
  31. GRB 230618A: Swift-XRT refined Analysis
  32. GRB 230616A: Swift-XRT observations
  33. LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
  34. GRB 230614B: Fermi GBM Observation
  35. GRB 230614C: Fermi GBM Detection
  36. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  37. GRB 230506B: Chandra localization of the X-ray afterglow
  38. GRB 230606A: Fermi GBM Observation
  39. GRB 230606A: Swift-XRT refined Analysis
  40. Fermi-LAT gamma-ray observations of IceCube-230603A
  41. LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  42. Alert from the HAWC Burst Monitor HAWC-230527A
  43. Fermi-LAT gamma-ray observations of IceCube-230524A
  44. GRB 230525A: Fermi GBM Detection
  45. GRB 230524A: Fermi GBM Observation
  46. GRB 230518A: Fermi GBM Observation
  47. LIGO/Virgo/KAGRA S230518h: Upper limits from Konus-Wind observations
  48. LIGO/Virgo S230518h: AGILE/MCAL observations
  49. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  50. LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  51. GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
  52. GRB 230510B: Fermi GBM detection
  53. GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  54. Fermi-LAT gamma-ray observations of IceCube-230511A
  55. GRB 230512A: Swift-XRT observations
  56. GRB 230512A: GIT optical follow-up ZTF candidates
  57. GRB 230512A: Fermi GBM detection
  58. GRB 230512A: Fermi-LAT detection
  59. GRB 230510A: GIT optical upper limits
  60. GRB 230510A: Fermi GBM detection
  61. GRB 230506B: Fermi GBM detection
  62. GRB 230510A: Swift-XRT refined Analysis
  63. GRB 230506C: Fermi GBM detection
  64. GRB 230506C: SAO RAS optical observations
  65. Fermi-LAT gamma-ray observations of IceCube-230506A
  66. GRB 230506C: Swift-XRT refined Analysis
  67. GRB 230506C: Swift/UVOT Upper Limits
  68. GRB 230506B: Swift-XRT refined Analysis
  69. GRB 230506C: Swift-XRT analysis
  70. GRB 230430A: Fermi GBM observation
  71. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  72. GRB 230427A: Swift-XRT refined Analysis
  73. GRB 230427A: GIT optical upper limit
  74. GRB 230426A: Fermi GBM Detection
  75. GRB 230423A: Swift-XRT refined Analysis
  76. GRB 230421A: Fermi GBM observation
  77. GRB 230420A: Swift-XRT refined Analysis
  78. GRB 230420A: NOT optical afterglow confirmation
  79. GRB 230402A: Fermi GBM detection
  80. GRB 230418A: Fermi GBM Observation
  81. GRB 230402A: Fermi-LAT detection
  82. Fermi-LAT gamma-ray observations of IceCube-230416A
  83. GRB 230415A: Fermi GBM detection
  84. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  85. GRB 230307A: iTelescope optical upper limit (likely)
  86. GRB 230414B: Lulin 40cm-SLT optical limit
  87. GRB 230414B: Swift-XRT refined Analysis
  88. GRB 230414B: 1.3m DFOT Optical observations
  89. GRB 230328B: redshift lower limit estimating
  90. GRB 230409B: Swift-XRT refined Analysis
  91. Fermi-LAT gamma-ray observations of IceCube-230405A
  92. GRB 230405B: Swift-XRT refined Analysis
  93. GRB 230405B: Fermi GBM Observation
  94. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  95. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  96. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  97. GRB 230328B: 3.6m DOT multiband optical observation
  98. GRB 230328B: Swift-XRT refined Analysis
  99. GRB 230328B: Fermi GBM observation
  100. GRB 230325A: Swift-XRT refined Analysis

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