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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"

26497 results found.

  1. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  2. The EP-WXT trigger 01709320726 is likely a flaring star
  3. GRB 260924A: COLIBRÍ optical observations
  4. EP260924a: J-band upper limit by SYSU 80cm infrared telescope
  5. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  6. GRB 260925A: Swift-XRT refined Analysis
  7. EP260924a: EP-FXT follow-up observation
  8. Swift Trigger 1513439 is probably not a GRB
  9. GRB 260925A: Swift/UVOT Upper Limits
  10. GRB 260924A: Extreme Isotropic-equivalent Gamma-ray Energy and encouragement for multiwavelength follow-up observations
  11. GRB 260923A: Glowbug gamma-ray detection
  12. GRB 260924A: Optical follow-up observations with Kinder
  13. GRB 260922A: Glowbug gamma-ray detection
  14. GRB 260925A: Enhanced Swift-XRT position
  15. GRB 260925A: COLIBRÍ optical upper limits
  16. GRB 260925A: FRAM-Auger optical limit
  17. GRB 260924A: Ondrejov D50 optical afterglow detection
  18. EP260924a: J-band upper limit with WINTER
  19. GRB 260924A: SVOM/GRM observation
  20. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  21. GRB 260925A: Swift detection of a burst
  22. EP260924a: EP-WXT detection of an X-ray transient
  23. GRB 260924A: J-band observations by the SYSU 80 cm infrared telescope
  24. GRB 260924A: Swift/UVOT Detection
  25. GRB 260924A: GROWTH-India Telescope optical observations
  26. GRB 260924A: Swift-XRT refined Analysis
  27. Konus-Wind detection of GRB 260922A
  28. GRB 260921A: SVOM/GRM observation
  29. GRB 260922A: COLIBRÍ Confirmation of the Optical Counterpart
  30. GRB 260924A: Fermi GRB Observation
  31. Konus-Wind detection of GRB 260921A (possible merger-origin)
  32. GRB 260924A: AstroSat CZTI detection
  33. GRB 260920A: SVOM/GRM observation
  34. GRB 260924A: NOT optical counterpart confirmation
  35. GRB 260924A: Enhanced Swift-XRT position
  36. The EP-WXT trigger 01709319842 is likely a flaring star
  37. GRB 260924A: Swift detection of a burst
  38. EP260806a: e-MERLIN detection at 5 GHz
  39. GRB 260922A: Ondrejov D50 optical limit
  40. Fermi-LAT Gamma-ray Observations of IceCube-260919A
  41. Fermi-LAT Gamma-ray Observations of IceCube-260916A
  42. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  43. GRB 260922A: J-band upper limit with WINTER
  44. GRB 260922A: Swift/UVOT Upper Limits
  45. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  46. GRB 260922A: COLIBRÍ optical upper limits
  47. GRB 260922A: Swift-XRT refined Analysis
  48. GRB 260922A: Enhanced Swift-XRT position
  49. Fermi-LAT Gamma-ray Observations of IceCube-260805A
  50. Konus-Wind detection of GRB 260810A
  51. GRB 260920A: Glowbug gamma-ray detection
  52. GRB 260918A: SVOM/ECLAIRs refined analysis
  53. GRB 260922A: SVOM/C-GFT optical upper limit
  54. GRB 260922A: Swift detection of a burst
  55. GRB 260917C: AstroSat CZTI detection
  56. GRB 260921A: AstroSat CZTI detection
  57. GRB 260921A: Fermi GBM Observation
  58. GRB 260917B:: SVOM/ECLAIRs refined analysis
  59. The EP-WXT trigger 01709319528 is likely a flaring star
  60. EP260920a: VLT/HAWK-I near-infrared candidate
  61. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  62. EP260920b: LCO observations
  63. GRB 260920A: AstroSat CZTI detection
  64. EP260920b: SVOM/VT optical observation
  65. EP260920b: refined analysis of the EP-WXT and EP-FXT observations
  66. EP260920b: COLIBRÍ optical observations
  67. EP260920b: LCO optical counterpart detection
  68. The EP-WXT trigger 01709318601 is likely a flaring star
  69. EP260920b: Einstein Probe detection of an X-ray transient
  70. IceCube-260919A: Upper limits from a search for additional neutrino events in IceCube
  71. EP-WXT detected a brightening of HMXB LS V +44 17
  72. EP260920a: NOT early time optical upper limits
  73. EP260920a: NOT optical upper limits
  74. EP260920a: SVOM/VT optical upper limits
  75. EP260920a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  76. EP260920a: COLIBRÍ optical upper limits
  77. EP260917b: EP-FXT non-detection and upper limit
  78. EP260920a: LCO optical counterpart candidate
  79. EP260920a: Einstein Probe detection of an X-ray transient
  80. GRB 260915A: VLT optical and near-infrared upper limits
  81. EP260917a: refined analysis of the EP-FXT observations
  82. The EP-WXT trigger 01709318491 is likely a flaring star
  83. EP260917a: SVOM/VT optical upper limits
  84. GRB 260918A: SVOM/C-GFT optical upper limits
  85. Konus-Wind detection of GRB 260916B (short/hard)
  86. The EP-WXT trigger 01709318279 is likely a flaring star
  87. GRB 260916B: Glowbug gamma-ray detection of a short burst
  88. GRB 260918A: EP-FXT follow-up observation
  89. GRB 260917B: Mondy optical upper limit
  90. EP260917b: EP-WXT detection of an X-ray transient
  91. EP260917A: J-band upper limit with WINTER
  92. GRB 260917B: EP-FXT follow-up observation
  93. EP260917a: COLIBRÍ optical upper limits
  94. GRB 260915A: Swift-XRT afterglow detection
  95. GRB 260918A: LCO optical upper limits
  96. EP260917a: Einstein Probe detection of an X-ray transient
  97. GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  98. GRB 260918A: SVOM detection of a burst
  99. GRB 260917B: FRAM-Auger optical limits
  100. GRB 260916B: Fermi GBM Detection

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