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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"

23588 results found.

  1. GRB 251128A: Fermi GBM Final Real-time Localization
  2. GRB251126A: Continued optical observation from 1.3m DFOT
  3. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  4. GRB 251126A: 1.3m DFOT optical afterglow detection
  5. GRB 251125B: GECAM-B detection
  6. Fermi GRB 251127A: Global MASTER-Net observations report
  7. GRB 251127A: Fermi GBM Final Real-time Localization
  8. GRB 251126A: Asiago i-band detection
  9. Swift GRB 251126A: Global MASTER-Net observations report
  10. GRB 251121A: Fermi GBM Observation
  11. GRB 251126A: Swift detection of a burst
  12. EP251124b follow-up observation by EP-FXT
  13. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  14. Fermi GRB 251125B: Global MASTER-Net observations report
  15. GRB 251125B: Fermi GBM Final Real-time Localization
  16. EP251124b: Global MASTER-Net observations report
  17. EP251124a: Xinglong GWAC-F60A optical observation
  18. Fermi GRB 251125A: Global MASTER-Net observations report
  19. GRB 251125A: Fermi GBM Final Real-time Localization
  20. EP251124a: Global MASTER-Net observations report
  21. GRB 251124A: Fermi GBM Localization by automated pipeline
  22. GRB 251122B: Fermi GBM Final Localization
  23. Fermi GRB 251124a: Global MASTER-Net observations report
  24. GRB 251124a: Fermi GBM Final Localization
  25. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  26. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  27. EP251124a: GROWTH-India Telescope optical upper limits
  28. GRB 251116C: Swift-XRT confirmation of fading
  29. GRB 251122A/EP251122a: FTW optical and NIR observations
  30. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  31. The EP-WXT trigger 01709248783 is likely a flaring star
  32. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  33. EP251118A: 3.6m DOT optical afterglow detection
  34. GRB 251122A / EP251122a: EP-FXT counterpart detection
  35. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  36. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  37. GRB 251122A / EP251122a: LCO optical upper limits
  38. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  39. EP251122a: Global MASTER-Net observations report
  40. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  41. GRB 251122A / EP251122a: SVOM detection of a long burst
  42. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  43. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  44. EP251118a: Xinglong-2.16m optical observation
  45. GRB 251115A: Fermi GBM Observation
  46. The EP-WXT trigger 01709248635 is likely a flaring star
  47. GRB 251121A: Fermi GBM Final Real-time Localization
  48. Fermi trigger No 785388351: Global MASTER-Net observations report
  49. EP251118A: 1.3m DFOT optical afterglow detection
  50. GRB 251118A: Glowbug gamma-ray detection
  51. GRB 251118A: Fermi GBM Observation
  52. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  53. GRB 251118A: GECAM-B detection
  54. EP251118a / GRB 251118C: SVOM/VT optical observation
  55. The EP-WXT trigger 01709248403 is likely a flaring star
  56. GRB 251118A: NuSTAR detection of bright prompt emission
  57. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  58. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  59. GRB 251117A: Swift-XRT observations
  60. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  61. Konus-Wind detection of GRB 251118C (EP251118a)
  62. GRB 251116D: SVOM/GRM observation of a long GRB
  63. GRB 251119A: SVOM detection of a possible burst
  64. EP251118a: Global MASTER-Net observations report
  65. LAT GRB251118.86: Global MASTER-Net observations report
  66. GRB 251118A: Fermi-LAT detection
  67. Fermi GRB 251118B: Global MASTER-Net observations report
  68. GRB 251118B: Fermi GBM Final Real-time Localization
  69. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  70. GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
  71. GRB 251118A: Fermi GBM Final Real-time Localization
  72. GRB 251116C: SVOM/ECLAIRs refined analysis
  73. GRB 251116B: SVOM/ECLAIRs refined analysis
  74. GRB 251114B: GECAM-B detection of a short burst
  75. GRB 251117A: Fermi GBM observation
  76. LIGO/Virgo/KAGRA S251117dq: Updated Sky localization
  77. GRB 251115A: Swift-XRT observations
  78. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  79. GRB 251117A: SVOM/GRM observation of a short burst
  80. GRB 251117A: Fermi-LAT detection
  81. LAT GRB251117.51: Global MASTER-Net observations report
  82. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  83. GRB 251116C: Swift/BAT arcminute localization of a burst
  84. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  85. GRB 251116B: SVOM/VT optical upper limit
  86. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  87. LIGO/Virgo/KAGRA S251116en: Updated Sky localization
  88. GRB 251117A: Fermi GBM Final Localization Correction
  89. GRB 251116D: Glowbug gamma-ray detection
  90. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  91. GRB 251116C: SVOM/VT optical upper limit
  92. GRB 251116B: EP-FXT follow-up observation
  93. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  95. GRB 251116B: LCO optical upper limits
  96. GRB 251116C: LCO optical upper limits
  97. SVOM GRB251116C: Global MASTER-Net observations report
  98. GRB 251116C: SVOM detection of a burst
  99. GRB 251116B: SVOM detection of a burst
  100. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube

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