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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.

"N/A_MC151012A_R1" does not adhere to advanced search syntax. Please refer to the documentation and try again.
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"

10918 results found.

  1. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  2. EP260223a: Xinglong optical upper limit
  3. sb26021801: SVOM/VT optical upper limits
  4. GRB 260223A: SVOM/VT optical observation
  5. EP260221a: Optical upper limit with Kinder observations
  6. EP260214b: Mondy optical observations
  7. EP260210a: Mondy optical upper limits
  8. GRB 260208A: AbAO and Terskol optical upper limits
  9. GRB 260208A: continued Mondy optical observations
  10. EP260214b: Optical upper limit with Kinder observations
  11. EP260214a: Optical upper limits with Kinder observations
  12. EP260214a: VLT near-infrared observation
  13. EP260214b: SVOM/VT optical observation
  14. EP260214b: OHP/T120 optical observations
  15. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  16. GRB 260211A: SVOM/VT optical counterpart
  17. EP260214a: SVOM/VT optical upper limits
  18. EP260213a: Optical upper limits with Kinder observations
  19. EP260213a: SVOM/VT optical upper limit
  20. EP260213a: Mondy R-band optical upper limit
  21. GRB 260211A: SVOM/VT optical observation
  22. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  23. EP260210a: Optical upper limits with Kinder observations
  24. EP260210a: SVOM/VT optical upper limit
  25. GRB 260208B: refined analysis of the EP-FXT observation
  26. GRB 260131A/B: continued Mondy optical observations
  27. GRB 260208A: Mondy optical observations
  28. GRB 260208B: EP-FXT observation
  29. GRB 260208B: SVOM/VT optical candidate
  30. GRB 260208A: SVOM/VT optical observation
  31. GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box
  32. GRB 260207A : MASTER optical counterpart discovery
  33. GRB 260131A/B: Mondy and Terskol optical observations
  34. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  35. GRB 260204A: SVOM/VT confirms fading of the optical afterglow
  36. GRB 260204A: SVOM/VT optical candidate
  37. GRB 260204A : MASTER Global robotic net optical observations
  38. GRB 260131A/B: OHP/T193 optical observations
  39. EP260131a: SVOM/VT optical observation
  40. EP260131a: VLT/X-shooter spectroscopic redshift z = 0.937
  41. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  42. GRB 260131B: MAXI/GSC detection
  43. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  44. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  45. EP260128a: NOT optical counterpart candidate
  46. EP260128a: LCO optical upper limits
  47. EP260126a: SVOM/VT optical upperlimit
  48. GRB 260127A: Fermi GBM Observation
  49. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  50. Swift GRB 260127A: Global MASTER-Net observations report
  51. GRB 260127A: Swift detection of a burst
  52. EP260126a: Optical upper limit with Kinder observations
  53. EP260126a: Liverpool Telescope optical upper limits
  54. EP260126a: Further NOT optical upper limits
  55. GRB 260114A: SVOM/VT optical upper limits
  56. EP260119a: Assy AZT-20 optical observations
  57. EP260119a: Mondy and SAO RAS optical upper limits
  58. EP260119A: Mondy I-Band Observations
  59. GRB 251202A: further radio observations with the VLA
  60. EP260119a: SVOM/VT optical observation
  61. GRB 260117A: ZTSh optical upper limit
  62. GRB 260110A: SVOM detection of a burst through offline search
  63. Swift trigger on the HMXB 1A 1118-61
  64. GRB 260117A: SVOM/VT optical candidate
  65. GRB 260114A: VLT/MUSE spectroscopic observations
  66. EP260116a: Xinglong optical upper limit
  67. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  68. GRB 251222A: radio detection with the VLA
  69. GRB 260114A : MITSuME Akeno optical upper limits
  70. GRB 260114A: Mondy optical observations
  71. GRB 260114A: Swift detection of a short burst
  72. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  73. GRB 251230A: Mondy Optical Observations
  74. EP260110a: SVOM/VT optical upper limits
  75. Swift Trigger 1434591: possible GRB 260109C
  76. GRB 260102A: AbAO optical observations
  77. EP260105a: SVOM/VT optical upperlimit
  78. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  79. GRB 260101A: Swift/UVOT Detection
  80. GRB 260102A: SVOM/VT optical counterpart
  81. GRB 260101A: NOT spectroscopic observations
  82. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  83. GRB 260101A: Swift detection of a burst with an optical counterpart
  84. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  85. GRB 251230A: GRANDMA/TAROT Early Detection
  86. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  87. EP251229a: Optical upper limit with Kinder observations
  88. GRB 251222A: Mondy Optical Observations
  89. GRB251230A: 7DT optical upper limits
  90. GRB 251230A / EP251230a: SVOM/VT optical observation
  91. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  92. GRB 251222A/EP251222b: Optical detection with Kinder observations
  93. EP251222a: Optical upper limit with Kinder observations
  94. GRB 251222A: AbAO optical observations
  95. GRB 251222A: ZTSH BVRI optical observations
  96. EP251220a: CrAO ZTSh optical observations
  97. EP251221a: PRIME upper limit
  98. GRB251221A: 7DT optical upper limits
  99. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  100. GRB 251222A: PRIME near-infrared detection

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