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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"

44271 results found.

  1. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  2. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  3. GRB 241120A: GRBAlpha detection
  4. GRB 241113B: SVOM/VT optical afterglow observations
  5. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  6. Konus-Wind detection of GRB 241117A
  7. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  8. GRB 241105A: ATCA radio detection
  9. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  10. IPN triangulation of GRB 241117A
  11. GRB 241026A: VIRT Optical Upper Limit
  12. GRB 241025A: VIRT Optical Upper Limit
  13. Konus-Wind detection of GRB 241120A
  14. GRB241120A: OHP/T193 optical observations
  15. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  16. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  17. EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
  18. EP-WXT trigger 01709018832: Lick/Kast spectroscopy with the 3 m Shane telescope
  19. GRB 241120A: Mondy and AbAO optical observations
  20. EP241119a: Optical upper limits with Kinder observations
  21. EP trigger ID 01709122294: the X-ray transient is likely a stellar flare event
  22. EP241119a: GIT optical upper limits
  23. GRB 241113A: Possible ATCA Radio detection
  24. EP241119a : J-band observations with WINTER
  25. GRB 241120A: Fermi GBM Observation
  26. GRB 241114B: Insight-HXMT/HE detection
  27. Integral GRB241120.25: Global MASTER-Net observations report
  28. EP241119a: Global MASTER-Net observations report
  29. EP241119a: EP detection of a fast X-ray transient
  30. GRB241120A: a long GRB detected by INTEGRAL
  31. GRB 241120A: Fermi GBM Final Real-time Localization
  32. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  33. GRB 241112B: Mephisto further optical observations
  34. GRB 241119A: Fermi GBM Final Real-time Localization
  35. GRB 241030A: J-band observations
  36. GRB 241115a: PRIME near-infrared upper limits
  37. GRB 241117A: Swift/BAT-GUANO localization skymap of a burst
  38. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  39. GRB 241115B: Fermi GBM Observation
  40. LIGO/Virgo/KAGRA S241114y: Updated Sky localization
  41. Fermi GRB 241118A: Global MASTER-Net observations report
  42. GRB 241118A: Fermi GBM Final Real-time Localization
  43. Updates to IceCube realtime alert system for muon tracks
  44. GRB 241117A: SVOM/GRM observation of a short burst with extended emission
  45. GRB 241117A: Fermi GBM Detection
  46. Fermi GRB 241117B: Global MASTER-Net observations report
  47. GRB 241117B: Fermi GBM Final Real-time Localization
  48. IceCube-Cascade 241116A: Upper limits from a search for additional neutrino events in IceCube
  49. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  50. GRB 241115B: Swift/BAT-GUANO localization skymap of a long burst
  51. Fermi GRB 241117A: Global MASTER-Net observations report
  52. GRB 241117A: Fermi GBM Final Real-time Localization
  53. GRB 241115C: Fermi GBM Observation
  54. GRB 241115A: Swift-XRT afterglow detection
  55. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  56. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  57. GRB 241115A: Mephisto upper limits
  58. GRB 241113B: Mephisto upper limits
  59. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  60. GRB 241115D / EP 241115a: SVOM/GRM observation
  61. The EP-WXT trigger 01709120856 is likely a flaring star
  62. EP241113a: Swift XRT weak detection
  63. GRB 241115A: Fermi GBM Observation
  64. GRB 241115A: LCOGT Optical Upper Limits
  65. GRB 241115C: Swift/BAT-GUANO localization skymap of a burst
  66. Fermi GRB 241115B: Global MASTER-Net observations report
  67. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  68. EP241115a: Global MASTER-Net observations report
  69. GRB 241115B: Fermi GBM Final Real-time Localization
  70. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  71. EP241115a: EP detection of a fast X-ray transient
  72. EP241113a: No Detection in Fermi-GBM Observations
  73. Swift GRB 241115A: Global MASTER-Net observations report
  74. Fermi GRB 241115A: Global MASTER-Net observations report
  75. GRB 241115A: Swift detection of a burst
  76. GRB 241115A: Fermi GBM Final Real-time Localization
  77. EP 241113a: LBT possible optical counterpart
  78. GRB 241113B: KAIT Optical Afterglow Candidate
  79. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  80. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  81. GRB 241113A: Swift-BAT refined analysis
  82. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  83. GRB 241113A: PRIME near-infrared upper limits
  84. Fermi GRB 241114A: Global MASTER-Net observations report
  85. EP241113a: Global MASTER-Net observations report
  86. GRB 241114A: Fermi GBM Final Real-time Localization
  87. GRB 241113B: J-band upper limit from WINTER
  88. GRB 241113A: J-band observations with WINTER
  89. EP241113a : J-band observations with WINTER
  90. GRB 241030A: LCO optical observation
  91. GRB 241113B: Swift-XRT observations
  92. IceCube-241113A: Upper limits from a search for additional neutrino events in IceCube
  93. GRB 241113A: 1.6m Mephisto and 50cm array optical upper limits
  94. GRB 241113A: KAIT optical observations
  95. EP241113b: Global MASTER-Net observations report
  96. EP241113b/GRB 241113B: EP detection of GRB 241113B
  97. Fermi-LAT gamma-ray observations of IceCube-241113A
  98. GRB 241113B: SVOM/GRM observation
  99. EP241113a: EP on-board trigger and autonomous follow-up observation
  100. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate

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