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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

45676 results found.

  1. EP251023a: UAFO and AbAO optical observations
  2. GRB 251116D: AstroSat CZTI detection
  3. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  4. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  5. GRB 251116C: SVOM/VT optical upper limit
  6. GRB 251025B: further Mondy optical observations
  7. GRB 251111A: Mondy optical upper limit
  8. GRB 251116B: EP-FXT follow-up observation
  9. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  11. GRB 251116B: LCO optical upper limits
  12. GRB 251116C: LCO optical upper limits
  13. SVOM GRB251116C: Global MASTER-Net observations report
  14. GRB 251116C: SVOM detection of a burst
  15. GRB 251116B: SVOM detection of a burst
  16. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 251116A: Fermi GBM Final Real-time Localization
  18. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  19. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  20. GRB 251115A: Tiled Swift observations
  21. GRB 251115A: Fermi-LAT detection
  22. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  23. Fermi GRB 251115A: Global MASTER-Net observations report
  24. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume
  25. GRB 251115A: Fermi GBM Final Real-time Localization
  26. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  27. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  28. GRB 251113A: Glowbug gamma-ray detection
  29. GRB 251113A: AstroSat CZTI detection
  30. GRB 251114B: Fermi GBM Final Real-time Localization
  31. GRB 251112A: Swift-BAT refined analysis
  32. Konus-Wind detection of GRB 251108C
  33. Fermi trigger No 784717756: Global MASTER-Net observations report
  34. Konus-Wind detection of GRB 251103A
  35. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  36. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  37. IPN triangulation of GRB 251108C
  38. The EP-WXT trigger 01709248221 is likely a flaring star
  39. Fermi GRB 251114A: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  41. GRB 251114A: Fermi GBM Final Real-time Localization
  42. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  43. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  44. Fermi GRB 251113A: Global MASTER-Net observations report
  45. GRB 251113A: BALROG localization (Fermi Trigger 784748255 / GRB 251113734)
  46. GRB 251113A: Fermi GBM Final Real-time Localization
  47. GRB 251111A: SVOM/ECLAIRs refined analysis
  48. GRB 251025B: SVOM/ECLAIRs refined analysis
  49. Fermi Gamma-ray Burst Monitor trigger 784717756/251113381 is not a GRB
  50. GRB 251112A: Swift/UVOT Upper Limits
  51. LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
  52. GRB 251112A: Swift-XRT refined Analysis
  53. GRB 251108C: AstroSat CZTI detection
  54. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  55. GRB 251112B: MAXI/GSC detection
  56. Fermi Gamma-ray Burst Monitor trigger 784687703/251113034 is not a GRB
  57. Fermi Gamma-ray Burst Monitor trigger 784687099/251113027 is not a GRB
  58. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  59. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  60. GRB 251108B: Glowbug gamma-ray detection
  61. Swift Trigger 1413695: a possible GRB 251112A
  62. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  63. Fermi trigger No 784621743: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 3-Initial Localization Volume
  65. Fermi Gamma-ray Burst Monitor trigger 784653403/251112637 is not a GRB
  66. GRB251111A: 1.3m DFOT optical upper limit
  67. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  68. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  69. GRB 251111A: Swift-XRT afterglow detection
  70. GRB 251111A: SVOM/VT optical observations with X-band data
  71. SVOM GRB251111.42: Global MASTER-Net observations report
  72. GRB 251111A: Swift-XRT observations
  73. SVOM GRB251111.22: Global MASTER-Net observations report
  74. GRB 251111A: EP-FXT counterpart detection
  75. GRB 251013C: Chandra X-ray observations and jet break detection
  76. GRB 251111A: SVOM/VT optical observations with VHF data
  77. GRB 251111A: KAIT optical upper limit
  78. GRB 251111A: LCO optical observation
  79. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  80. GRB 251111A: SVOM detection of a soft burst
  81. GRB 251103B: Swift-BAT refined analysis
  82. GRB 251106A: Swift/UVOT Upper Limits
  83. GRB 251105B: Insight-HXMT/HE detection
  84. GRB 251106B: Insight-HXMT detection
  85. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  86. GRB 251105A: AstroSat CZTI detection
  87. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  88. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  89. LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
  90. LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
  91. GRB 251108A: Fermi GBM Final Localization Correction
  92. Fermi trigger No 784329591: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  94. Fermi trigger No 784279167: Global MASTER-Net observations report
  95. SVOM GRB251108.54: Global MASTER-Net observations report
  96. GRB 251102B: SVOM/GRM observation
  97. Fermi Gamma-ray Burst Monitor trigger 784279167/251108305 is not a GRB
  98. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  99. The EP-WXT trigger 01709248051 is likely a flaring star
  100. SVOM GRB251106.83: Global MASTER-Net observations report

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