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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"

27392 results found.

  1. EP260822a: Global MASTER-Net observations report
  2. EP Alert 260820.31: Global MASTER-Net observations report
  3. GRB 260807A: EP-FXT follow-up observations
  4. GRB 260822A: SVOM/ECLAIRs refined analysis
  5. GRB 260809A: SVOM/ECLAIRs refined analysis
  6. IceCube Alert 260825A: Global MASTER-Net observations report
  7. GRB 260825A: Fermi GBM Final Real-time Localization
  8. GRB 260822A: EP/FXT follow-up observations
  9. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  10. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  11. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  12. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  13. GRB 260822A: LCO optical upper limits
  14. The EP-WXT trigger 01709287395 is likely a flaring star
  15. GRB260822B: Fermi GBM Final Localization
  16. GRB 260822A: GROWTH-India Telescope Upper Limits
  17. GRB 260822A: GOTO optical upper limit
  18. GRB 260822A: SVOM detection of a short burst
  19. GRB 260818B: SVOM/C-GFT optical upper limit
  20. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  21. IceCube Alert 260821A: Global MASTER-Net observations report
  22. The EP-WXT trigger 01709286204 is likely a flaring star
  23. GRB260820A: Fermi GBM Final Real-Time Localization
  24. GRB 260818B: EP-FXT follow-up observation
  25. GRB 260818A: J-band observations with WINTER
  26. GRB 260818B: SVOM/ECLAIRs refined analysis
  27. GRB 260818A: SVOM/ECLAIRs refined analysis
  28. GRB 260818B: NOT optical upper limits
  29. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  30. GRB260818A: EP-FXT follow-up observation
  31. GRB 260818B: LCO optical upper limits
  32. GRB 260818B: SVOM detection of a short burst
  33. SVOM trigger sb26081806 is not a GRB
  34. EP260806a: SAO RAS multicolor optical observations
  35. GRB 260818A: LCO optical upper limits
  36. EP260812a: AbAO optical upper limit
  37. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  38. GRB 260818A: SVOM possible detection of a long and faint GRB
  39. EP260806a: SVOM/ECLAIRs detection through targeted search
  40. The EP-WXT trigger 01709281429 is likely a flaring star
  41. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  42. EP260806a: WFST optical observations
  43. The EP-WXT trigger 01709280562 is likely a flaring star
  44. The EP-WXT trigger 01709279838 is likely a flaring star
  45. GRB 260808B: Liverpool Telescope further optical observations
  46. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  47. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  48. GRB 260813A: Fermi GBM Final Real-time Localization
  49. EP260812a: NOT and Liverpool Telescope upper limits:
  50. EP260812a: SVOM/C-GFT optical upper limit
  51. EP260812b: COLIBRÍ optical observations
  52. EP260812b: SVOM/VT optical observation
  53. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  54. Fermi GBM Sub-Threshold Detection of GRB 260809A
  55. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  56. GRB 260808B: SVOM/VT optical re-brightening at day 3
  57. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  58. GRB 260806A: CALET Gamma-Ray Burst Monitor detection
  59. GRB 260807A: SVOM/ECLAIRs refined analysis
  60. GRB260808B: MAO/AZT-22 optical observations
  61. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  62. GRB 260809A: J-band upper limit with WINTER
  63. EP260809a: VLT/X-shooter spectroscopic redshift z = 3.07
  64. GRB 260806A: Glowbug gamma-ray detection
  65. GRB 260808A: CALET Gamma-Ray Burst Monitor detection
  66. GRB 260805C: CALET Gamma-Ray Burst Monitor detection
  67. GRB 260804A: CALET Gamma-Ray Burst Monitor detection
  68. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  69. The EP-WXT trigger 01709278015 is likely a flaring star
  70. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  71. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  72. GRB 260809A: NOT optical observations
  73. GRB260809A: MAO/AZT-22 optical observations
  74. GRB260809A: OHP/T193 optical observations
  75. GRB 260809A: SVOM/VT optical counterpart
  76. EP260809a: J-band upper limit with WINTER
  77. GRB 260808B: J-band upper limit with WINTER
  78. GRB 260808B: SVOM/ECLAIRs refined analysis
  79. GRB 260809A: SVOM detection of a faint burst
  80. GRB 260808B: Liverpool Telescope optical observations
  81. GRB 260808B: NOT optical observations
  82. GRB 260808B: LCO optical observations
  83. EP260809a: COLIBRÍ optical observations
  84. EP260809a: LCO optical observation
  85. EP260809a: OHP/T193 optical observations
  86. GRB260808B: OHP/T193 optical observations
  87. GRB 260808B / EPF_J230056.0+082842: EP-FXT follow-up observation
  88. GRB 260808B: SVOM/VT optical afterglow confirmation
  89. GRB 260808C: Fermi GBM Final Real-time Localization
  90. GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
  91. GRB 260808B: SVOM/VT optical candidate from VHF data
  92. GRB 260808B: SVOM detection of a faint burst
  93. GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
  94. Fermi GRB 260808A: Global MASTER-Net observations report
  95. GRB 260808A: Fermi GBM Final Real-time Localization
  96. IceCube Alert 260807A: Global MASTER-Net observations report
  97. GRB 260807A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  98. GRB 260807A: SVOM possible detection of a faint burst
  99. EP260806a: COLIBRÍ optical observations
  100. EP260806a: SVOM/VT optical observation

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