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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"

32689 results found.

  1. EP EP241026b: Global MASTER-Net observations report
  2. GRB 241026A: KAIT optical observations
  3. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  4. GRB 241026A: SAO RAS observations of possible optical afterglow
  5. Fermi GRB 241026A: Global MASTER-Net observations report
  6. GRB241025A: 1.3m DFOT optical afterglow detection
  7. EP241021a: optical follow-up observations with Xinglong Observatory
  8. ​GRB 241025A: optical photometry from Konkoly
  9. GRB 241025A: GROWTH-India Telescope optical observations
  10. GRB 241025A: COLIBRÍ Detection of the Afterglow
  11. GRB 241025C: Fermi GBM Detection
  12. GRB 241025A: Fermi GBM Observation
  13. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  14. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  15. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  16. EP 241021a: Swift-XRT observations
  17. EP241021a: optical follow-up observations with the Liverpool Telescope
  18. Fermi GRB 241025A: Global MASTER-Net observations report
  19. Swift GRB 241025A: Global MASTER-Net observations report
  20. EP241025a (GRB 241025A): EP observations update
  21. GRB 241025A : SVOM/VT optical afterglow observations
  22. EP 241021A: Swift ToO observations
  23. EP241021a: Liverpool Telescope optical follow-up observations
  24. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  25. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  26. GRB 241025A: DDOTI Afterglow detection
  27. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  28. GRB 241025A: SVOM/GRM observation
  29. GRB 241025A: TRT optical afterglow observation
  30. Fermi GRB 241024B: Global MASTER-Net observations report
  31. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  32. GRB 241001A: ATCA radio observations
  33. EP241021a: No Detection in Fermi-GBM Observation
  34. GRB 241010A: VIRT Optical Upper Limit
  35. EP241021a: VLT/FORS2 redshift z = 0.75
  36. EP241021a: SAO RAS optical observations
  37. EP241021a: KAIT optical observations
  38. EP241021a: EP-FXT follow-up observation update
  39. IPN triangulation of GRB 241021A (long)
  40. EP241021a: Optical counterpart observations with the Liverpool Telescope
  41. EP241021a: 1.3m DFOT Optical observations
  42. EP241021a: GSP detects optical candidate counterpart
  43. EP241021a: Optical upper limits with Kinder observations
  44. EP241021a: TRT optical observations
  45. GRB 241018A: SVOM/C-GFT optical observations
  46. EP241021a: NOT likely optical counterpart
  47. EP EP241021a: Global MASTER-Net observations report
  48. GRB241017A: 1.3m DFOT optical upper limit
  49. GRB 241018A: 1.3m DFOT Optical upper limit
  50. GRB 241018A: EP-FXT afterglow detection
  51. EP241021a: GOTO optical upper limits
  52. Konus-Wind detection of GRB 241018A
  53. GRB 241018A: SVOM/GRM observation
  54. GRB 241018A/sb24101802: Mephisto optical upper limit
  55. GRB 241017A/sb24101702: Mephisto optical upper limit
  56. GRB 241018A: Mondy optical upper limit
  57. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  58. GRB 241018A: GROWTH-India telescope optical upper limit
  59. GRB241018A: XingLong Optical Upper Limit
  60. GRB 241018A: REM optical/NIR upper limits
  61. GRB 241018A: NOT optical observations
  62. GRB 241017A: SVOM/VT follow-up and optical upper limit
  63. GRB 241018A: SVOM/VT follow-up and optical candidate
  64. GRB 241018A: LCO/0.4m optical upper limits
  65. GRB 241018A: Swift ToO observations
  66. GRB 241006A: VIRT Optical Upper Limit
  67. GRB 240727A: VIRT Optical Upper Limit
  68. GRB 241018A: X-ray afterglow candidate observed by MXT
  69. GRB 241016B: Fermi GBM Observations
  70. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  71. GRB 241001A: EP-FXT afterglow detection
  72. GRB 241017A: GROWTH-India Telescope optical upper limit
  73. GRB241017A: TOO Observations by SVOM/MXT
  74. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  75. GRB 241017A: J-band upper limit from WINTER
  76. GRB 241016B: SVOM/GRM observation
  77. GRB 241017A: Swift ToO observations
  78. Fermi GRB 241016B: Global MASTER-Net observations report
  79. Fermi GRB 241016A: Global MASTER-Net observations report
  80. GRB 241010A: Swift-BAT refined analysis
  81. GRB 241013B: Fermi GBM Observation
  82. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  83. GRB 241013A: Fermi GBM Observation
  84. GRB 240916A: radio detection with the VLA
  85. GRB241013A: REM observations
  86. GRB 241009A: LCO optical upper limits
  87. GRB 241013B: SVOM/GRM observation
  88. Fermi GRB 241013B: Global MASTER-Net observations report
  89. GRB 241013A: a long GRB detected by INTEGRAL
  90. LIGO/Virgo/KAGRA S241009em: Updated Sky localization
  91. LIGO/Virgo/KAGRA S241011k: Updated Sky localization
  92. LIGO/Virgo/KAGRA S241011k: Identification of a GW compact binary merger candidate
  93. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  94. GRB 241009A: GRANDMA optical upper limits
  95. GRB 241010A: JinShan optical observations and potential host galaxy
  96. GRB 241006A: ATCA Radio Upper Limits
  97. LIGO/Virgo/KAGRA S241007bw: Updated Sky localization
  98. Swift GRB 241010A: Global MASTER-Net observations report
  99. GRB 241010A: J-band observations with WINTER
  100. LIGO/Virgo/KAGRA S241009an: Updated Sky localization

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