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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"

44417 results found.

  1. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  2. EP241103a: GSP optical upper limit
  3. EP241103A: LCO optical observations
  4. EP241103a: Global MASTER-Net observations report
  5. EP241103a: an X-ray transient detected by Einstein Probe
  6. GRB 241030A: Rapid release of TESS data.
  7. EP241101a: Global MASTER-Net observations report
  8. GRB 241029A: GRBAlpha detection
  9. EP241101a: BOOTES-7 optical upper limit
  10. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  11. S241102cy: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  13. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  14. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  15. GRB241030A: OHP/T193 optical observations
  16. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  17. EP241101a: EP-WXT detection of a fast X-ray transient
  18. Swift GRB 241101A: Global MASTER-Net observations report
  19. GRB 241101A: FRAM-ORM optical limit
  20. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  21. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  22. EP241021a: Upper limit from Konus-Wind observations
  23. GRB 241101A: Swift-BAT refined analysis
  24. GRB 241030A: further SAO RAS optical observations
  25. GRB 241030A: Optical Observations via Virtual Telescope Project
  26. EP241021a: Liverpool Telescope optical follow-up observations
  27. GRB 241030B: Swift-XRT refined Analysis
  28. GRB 241026A: SAO RAS optical observations
  29. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  30. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  31. GRB 241101A: Swift detection of a burst
  32. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  33. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  34. EP241021a: OHP/T193 optical observations
  35. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  36. GRB 241030B: Montarrenti Observatory optical upper limit
  37. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  38. EP241026b: Liverpool Telescope optical follow-up
  39. Fermi trigger No 752083996: Global MASTER-Net observations report
  40. GRB 241030A: SAO RAS optical observations
  41. GRB 241030A: Fermi GBM Observation
  42. EP241021a: AMI-LA radio detection
  43. GRB 241030B : GIT optical upper limits
  44. GRB 241030B: LCOGT Optical Upper Limits
  45. GRB 241030B: Swift-BAT refined analysis
  46. GRB 241030A: Swift-BAT refined analysis
  47. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  48. GRB 241030B: Swift/UVOT Detection
  49. EP EP241030a: Global MASTER-Net observations report
  50. GRB 241029A: LCO optical detection
  51. Fermi trigger No 752006065: Global MASTER-Net observations report
  52. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  53. Swift GRB241030.77: Global MASTER-Net observations report
  54. GRB 241030B: SVOM/GRM observation
  55. GRB 241030B : MITSuME Akeno optical upper limits
  56. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  57. GRB 241030B: SVOM/VT optical afterglow observations
  58. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  59. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  60. GRB241030B: Fermi GBM Observation
  61. GRB 241030B: BTA observations
  62. GRB 241029A: SVOM/VT optical afterglow observations
  63. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  64. GRB 241030B: Enhanced Swift-XRT position
  65. GRB 241030B: optical observations from the INAF Asiago Observatory
  66. EP241021a: Swift-UVOT detection
  67. GRB241030B: GRANDMA/TAROT Upper Limit
  68. GRB 241030A: Swift-XRT refined Analysis
  69. GRB 241030B: SAO RAS optical observations
  70. GRB 241030B: AKO Optical Afterglow Detection
  71. GRB 241030B: Nanshan/HMT optical afterglow detection
  72. GRB 241030B: SVOM/ECLAIRs detection of a burst
  73. GRB 241030B: Prompt enhanced Swift-XRT position
  74. Konus-Wind detection of GRB 241030A
  75. GRB 241030B: Swift detection of a burst
  76. GRB 241030B: Fermi GBM Final Real-time Localization
  77. GRB 241030A: Fermi-LAT detection
  78. GRB 240912A: radio detection with the VLA
  79. Fermi GRB 241030A: Global MASTER-Net observations report
  80. GRB 241030A: AKO Optical Afterglow Detection
  81. Swift GRB 241030A: Global MASTER-Net observations report
  82. GRB 241030A: Swift/UVOT Detection
  83. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  84. GRB 241030A: SVOM/GRM observation
  85. GRB 241026A: Swift-BAT refined analysis
  86. GRB 241030A: SVOM/C-GFT optical observations
  87. GRB 241026A: LBT optical observations
  88. EP241021a: Optical rebrightening observations with Mephisto
  89. EP241026b: EP-FXT follow-up observation
  90. GRB 241030A: Multiband optical detection with Mephisto
  91. GRB 241030A: SVOM/VT optical afterglow observations
  92. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  93. GRB 241030A : MITSuME Akeno optical afterglow detection
  94. GRB 241030A: Enhanced Swift-XRT position
  95. GRB 241029A: GROWTH-India Telescope optical follow up
  96. GRB 241030A: TRT optical observations
  97. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  98. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  99. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  100. GRB 241030A: Swift detection of a burst with a bright optical counterpart

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