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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"

32715 results found.

  1. GRB 241112B: GOTO optical upper limits
  2. GRB 241112B: Swift ToO observations
  3. GRB 241107A: INTEGRAL IBIS localization
  4. EP241107a: EP-FXT follow-up observations
  5. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  6. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  7. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  8. IPN triangulation of GRB 241107A (short/hard)
  9. GRB 241107A: INTEGRAL/IBIS/PICsIT detection of a short burst
  10. GRB 241025C: VZLUSAT-2 detection
  11. GRB 241025A: VZLUSAT-2 detection
  12. GRB 241018A: cubesat Avion detection
  13. GRB 241030B: TESS detection of optical counterpart
  14. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  15. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  16. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  17. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  18. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  19. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  20. EP241107a: AbAO optical upper limit
  21. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  22. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  23. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  24. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  25. EP241109a: confirmation of a stellar flare by BOOTES-7
  26. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  27. EP241107A: MASTER optical observations of xray transient
  28. EP241107a: KAIT optical observations
  29. GRB 241108A: Swift ToO observations
  30. GRB 241030A: TESS observations
  31. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  32. EP241107a: Kinder optical follow-up observations
  33. GRB 241025A: radio detection with the VLA
  34. GRB 241104A: CALET Gamma-Ray Burst Monitor detection
  35. EP241107a: AKO Optical Afterglow Follow-Up Observations
  36. EP241107a: GSP detects optical counterpart
  37. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  38. GRB 241105A: EP-FXT follow-up observations
  39. GRB 241105A: SVOM/GRM observation
  40. EP241107a: OHP/T193 photometric and spectroscopic observations
  41. GRB 241105a: PRIME near-infrared upper limits
  42. EP241107a: FTW Optical and NIR observations of the optical counterpart
  43. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  44. EP241107a: GIT optical observations
  45. EP241107a: Global MASTER-Net observations report
  46. EP241107a: SVOM/C-GFT optical observations
  47. EP241107a: AKO Optical Afterglow Detection
  48. GRB 241025A: LBT optical observations
  49. GRB241105A: Gemini-South Optical Afterglow Detection
  50. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  51. GRB 241105A: Swift/UVOT Detection
  52. EP241101a: CrAO ZTSH optical observations
  53. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  54. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  55. GRB 241030A: Mondy optical observations
  56. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  57. Konus-Wind detection of GRB 241105A (short with extended emission)
  58. Konus-Wind detection of GRB 241021A
  59. GRB 241105A: SVOM/VT optical afterglow observations
  60. GRB 241105A: Swift-XRT afterglow detection
  61. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  62. GRB 241104A: Swift-XRT observations
  63. GRB 240511A: LCO upper limits
  64. GRB 241104A: Fermi GBM Observation
  65. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  66. GRB 241105A: Swift ToO observations
  67. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  68. GRB 241104A: Swift ToO observations
  69. GRB 241104A: NOT optical non-detection
  70. GRB 241105A: GOTO tentative optical counterpart candidate
  71. Fermi GRB 241105A: Global MASTER-Net observations report
  72. GRB 241104A: SVOM/VT optical candidate
  73. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  74. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  75. GRB 241104A: SVOM/GRM observation
  76. EP241104a: EP detection of GRB 241104A X-ray emission
  77. GRB 241010A: host galaxy redshift z = 0.977
  78. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  79. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  80. GRB 240821A: further radio observations with the VLA
  81. Fermi GRB 241104A: Global MASTER-Net observations report
  82. GRB 241030A: GRBAlpha detection
  83. EP241101a: EP-FXT observations update
  84. EP241103a: GIT optical upper limit
  85. EP241021a: OHP/T193 further optical observations
  86. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  87. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  88. EP241103a: GOTO optical upper limit
  89. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  90. EP241101a: Possible detection of an optical counterpart with FTW
  91. EP241103a: Swift XRT detection and improved X-ray position
  92. EP241021a: continued SOAR observations
  93. EP241101a: Optical upper limits with Kinder observations
  94. EP241101a: OHP/T193 optical observations
  95. EP241103a: Gemini optical limits
  96. EP241103a: EP observation update
  97. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  98. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  99. EP241103a: GSP optical upper limit
  100. EP241103A: LCO optical observations

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