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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').
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32581 results found.

  1. EP251023a: UAFO and AbAO optical observations
  2. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  3. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  4. GRB 251116C: SVOM/VT optical upper limit
  5. GRB 251025B: further Mondy optical observations
  6. GRB 251111A: Mondy optical upper limit
  7. GRB 251116B: EP-FXT follow-up observation
  8. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  10. GRB 251116B: LCO optical upper limits
  11. GRB 251116C: LCO optical upper limits
  12. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  13. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  14. GRB 251115A: Tiled Swift observations
  15. GRB 251115A: Fermi-LAT detection
  16. GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
  17. Fermi GRB 251115A: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  19. LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
  20. GRB 251113A: Glowbug gamma-ray detection
  21. GRB 251113A: AstroSat CZTI detection
  22. GRB 251112A: Swift-BAT refined analysis
  23. Konus-Wind detection of GRB 251108C
  24. Konus-Wind detection of GRB 251103A
  25. LIGO/Virgo/KAGRA S251112cm: ATLAS targeted observations of the skymap
  26. IPN triangulation of GRB 251108C
  27. Fermi GRB 251114A: Global MASTER-Net observations report
  28. LIGO/Virgo/KAGRA S251112cm: Candidates from the Zwicky Transient Facility
  29. LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates
  30. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  31. Fermi GRB 251113A: Global MASTER-Net observations report
  32. GRB 251111A: SVOM/ECLAIRs refined analysis
  33. GRB 251025B: SVOM/ECLAIRs refined analysis
  34. GRB 251112A: Swift/UVOT Upper Limits
  35. LIGO/Virgo/KAGRA S251112cm: ATLAS pre-detections of AT2025adgp and AT2025adgq
  36. LIGO/Virgo/KAGRA S251112cm: Detection of two young transients by BlackGEM/MeerLICHT: AT2025adgp and AT2025adgq
  37. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  38. LIGO/Virgo/KAGRA S251112cm: Initial GOTO-South observations
  39. LIGO/Virgo/KAGRA S251112cm: Upper limits from Fermi-GBM Observations
  40. GRB251111A: 1.3m DFOT optical upper limit
  41. LIGO/Virgo/KAGRA S251112cm: Identification of a GW compact binary merger candidate
  42. GRB 251106B: Glowbug gamma-ray detection of a likely short burst
  43. GRB 251111A: SVOM/VT optical observations with X-band data
  44. GRB 251111A: Swift-XRT observations
  45. GRB 251111A: EP-FXT counterpart detection
  46. GRB 251013C: Chandra X-ray observations and jet break detection
  47. GRB 251111A: SVOM/VT optical observations with VHF data
  48. GRB 251111A: KAIT optical upper limit
  49. GRB 251111A: LCO optical observation
  50. GRB 251111A: SVOM/COLIBRÍ (FM-GFT) optical counterpart detection
  51. GRB 251103B: Swift-BAT refined analysis
  52. GRB 251106A: Swift/UVOT Upper Limits
  53. GRB 251105B: Insight-HXMT/HE detection
  54. GRB 251106B: Insight-HXMT detection
  55. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  56. GRB 251105A: AstroSat CZTI detection
  57. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  58. LIGO/Virgo/KAGRA S251108fi: Updated Sky localization
  59. LIGO/Virgo/KAGRA S251108dn: Updated Sky localization
  60. LIGO/Virgo/KAGRA S251108fi: Identification of a GW compact binary merger candidate
  61. GRB 251102B: SVOM/GRM observation
  62. LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
  64. LIGO/Virgo/KAGRA S251103f: Updated Sky localization
  65. IPN triangulation of GRB 251105B (possible sGRB with EE)
  66. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
  67. GRB 251106A: Swift-XRT afterglow detection
  68. GRB 251106A: Kilonova-Catcher optical upper limit
  69. Fermi GBM Sub-Threshold Detection of GRB 251106A
  70. GRB 251106A: Swift/BAT arcminute localization of a burst
  71. GRB 251106A: SVOM/COLIBRÍ (FM-GFT) detection of a likely optical counterpart
  72. GRB 251106A: MASTER optical observations
  73. GRB 251103B: AstroSat CZTI detection
  74. GRB 251025C: TERI Gamma-ray detection
  75. GRB 251016B: TERI Gamma-ray detection
  76. GRB 251016A: TERI Gamma-ray detection of a short burst
  77. GRB 250920C: TERI Gamma-ray detection
  78. EP251102a: Xinglong 2.16-m clear-band observations of the optical counterpart
  79. GRB 251105A: Fermi GBM Observation
  80. GRB 251105A: Swift/BAT-GUANO localization skymap of a burst
  81. GRB 251104A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  82. GRB 251105B: AstroSat CZTI detection of a short burst with extended emission
  83. GRB 251023A: SVOM/ECLAIRs detection of a burst through targeted search
  84. Fermi GBM Sub-Threshold Detection of GRB 251105B
  85. GRB 251103B: Swift/UVOT Upper Limits
  86. LIGO/Virgo/KAGRA S251105aj: Identification of a GW compact binary merger candidate
  87. Fermi GRB 251105A: Global MASTER-Net observations report
  88. GRB 251103B: Fermi GBM observation
  89. GRB 251028A: Insight-HXMT/HE detection
  90. GRB 251103A: Optical afterglow detection by ZTF’s public survey
  91. EP251102a: FTW optical and NIR observations
  92. GRB 251103A: WFST optical observations
  93. EP251102a: update of EP-FXT follow-up observation
  94. EP251102a: OHP/T193 optical observations
  95. GRB 251103A: OHP/T193 optical observations
  96. GRB 251103A: Xinglong 2.16m optical detection
  97. GRB 251103A: Insight-HXMT detection
  98. GRB 251103A: KAIT optical observations
  99. GRB 251103B: Nanshan/HMT optical upper limit
  100. GRB 251013C: 7DT detection and Medium-band SED of Afterglow

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