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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"

35984 results found.

  1. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  2. GRB 231015A: NuSTAR Detection of Prompt Emission
  3. Fermi GRB 231020A: Global MASTER-Net observations report
  4. GRB 231020A: Fermi GBM Final Real-time Localization
  5. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  6. GRB 231017A: 1.3m DFOT Optical upper limit
  7. IceCube-231004A: Upper limits from Fermi-GBM Observations
  8. GRB 231018A: GRBAlpha detection
  9. GRB 231018A: CALET Gamma-Ray Burst Monitor detection
  10. Fermi GRB 231019A: Global MASTER-Net observations report
  11. GRB 231018A: Glowbug gamma-ray detection
  12. Konus-Wind detection of GRB 231018A
  13. IPN triangulation of GRB 231018A
  14. GRB 231017A: Swift/UVOT Upper Limit
  15. GRB 230911C: ATCA detection of possible radio counterpart
  16. GRB 231019A: Fermi GBM Final Real-time Localization
  17. GRB 231017A: GOTO optical upper limits
  18. GRB 231017A: JinShan optical upper limit
  19. GRB 231018A: GROWTH-India Follow-Up of a Fermi Long GRB
  20. GRB 231017A: Las Cumbres optical upper limit
  21. GRB 231015A: Glowbug gamma-ray detection
  22. GRB 231017A: LCOGT Optical Upper Limits
  23. GRB231017A: GROWTH-India upper limits on the optical afterglow
  24. GRB 231015A: AstroSat CZTI detection
  25. GRB 231018A: Fermi GBM Detection
  26. GRB 231017A: Fermi GBM Detection
  27. GRB 231017A: Swift-XRT observations
  28. GRB 231012B may not be a GRB
  29. GRB 231018A: BALROG localization (Fermi Trigger / GRB 231018521)
  30. GRB 231018A: Fermi GBM Final Real-time Localization
  31. GRB 231017A: Swift ToO observations
  32. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  33. GRB231017A: Fermi GBM Final Localization
  34. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  35. Correction in GCN 34814: GRB 231012B (not GRB 231012A)
  36. GRB 231012A: Fermi GBM Final Real-time Localization
  37. GRB 231012A: Fermi GBM Final Real-time Localization
  38. GRB 231004A: Glowbug gamma-ray detection
  39. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  40. GRB 231004A: CALET Gamma-Ray Burst Monitor detection
  41. GRB 231004A: Fermi GBM Final Real-time Localization
  42. GRB 231003A is not a GRB
  43. GRB 231003A: Fermi GBM Final Real-time Localization
  44. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  45. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  46. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  47. GRB 230827B: 10.4m GTC spectroscopic redshift
  48. GRB 230930A: Fermi GBM Final Real-time Localization
  49. AT2023sva / GRB230916B: GIT observations of the afterglow
  50. transient AT2023sva: A Binary Driven Hypernova with a possible associated supernova
  51. Konus-Wind detection of GRB 230919A
  52. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  53. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  54. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  55. Fermi Gamma-ray Burst Monitor trigger 717299390/230925076 is not a GRB
  56. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  57. GRB 230812B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  58. GRB 230921A: Fermi GBM Final Real-time Localization
  59. GRB 230918B: VLT/X-shooter classification of AT 2023tbf (GOTO23aky) as a dwarf nova
  60. IPN triangulation of GRB 230919A (short)
  61. GRB 230919A: Fermi GBM Observation
  62. Fermi GBM Statement for Trigger 716527670/230916144
  63. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  64. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  65. GRB 230919A: AstroSat CZTI detection
  66. AT2023sva: redshift from OSIRIS+/GTC of the ZTF afterglow
  67. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  68. GRB 230919A: Fermi GBM Final Real-time Localization
  69. Detection of self-absorbed radio emission from GRB 230812B with the JVLA + uGMRT
  70. GRB 230918B: Fermi GBM Final Real-time Localization
  71. GRB 230918A (short): Glowbug gamma-ray detection
  72. GRB 230916B: Glowbug gamma-ray detection
  73. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  74. GRB 230915A: Fermi GBM observation
  75. GRB 230812B: Radio observations with the uGMRT
  76. GRB 230918A: Fermi GBM Final Real-time Localization
  77. GRB 230917A: AstroSat CZTI detection
  78. GRB 230915B: Glowbug gamma-ray detection
  79. GRB 230916A: NuSTAR Discovery of Prompt Emission from a Potential GRB
  80. GRB 230911A: Fermi GBM Observation
  81. GRB 230915A: Swift/BAT-GUANO detection of a burst
  82. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  83. GRB 230911D: GRBAlpha detection
  84. Swift Trigger 1192233 is not a GRB
  85. GRB 230906A: optical counterpart
  86. GRB 230911A: Swift-XRT afterglow detection
  87. GRB 230913A: CALET Gamma-Ray Burst Monitor detection
  88. GRB 230913A: Glowbug gamma-ray detection
  89. GRB 230812B: Bad Time Intervals for Fermi GBM data
  90. GRB 230913A: Fermi GBM Observation
  91. Swift Trigger 1191904 is not a GRB
  92. GRB 230911A: Swift ToO observations
  93. GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
  94. Fermi GRB 230913A: Global MASTER-Net observations report
  95. GRB 230911A: GOTO optical counterpart candidate
  96. GRB 230913A: Fermi GBM Final Real-time Localization
  97. GRB 230908A: CALET Gamma-Ray Burst Monitor detection
  98. GRB 230911D: NuSTAR Detection of Prompt Emission
  99. GRB 230911B: AstroSat CZTI detection
  100. GRB 230911C: Swift-XRT refined Analysis

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