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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"

20850 results found.

  1. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  2. GRB 241112B: Mephisto optical upper limits
  3. GRB 241112B: GOTO optical upper limits
  4. GRB 241107A: INTEGRAL IBIS localization
  5. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  6. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  7. IPN triangulation of GRB 241107A (short/hard)
  8. GRB 241018A: cubesat Avion detection
  9. GRB 241030B: TESS detection of optical counterpart
  10. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  11. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  13. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  14. EP241109a: KAIT photometry and 3 m Shane spectroscopy from Lick observatory
  15. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  16. EP241107a: AbAO optical upper limit
  17. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  18. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  19. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  20. GRB 241108A: Swift-XRT observations
  21. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  22. EP241107a: KAIT optical observations
  23. GRB 241030A: TESS observations
  24. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  25. EP241107a: Kinder optical follow-up observations
  26. GRB 241025A: radio detection with the VLA
  27. EP241107a: AKO Optical Afterglow Follow-Up Observations
  28. EP241107a: Gemini-South spectroscopic confirmation (z = 0.456)
  29. GRB 241105A: SVOM/GRM observation
  30. EP241107a: OHP/T193 photometric and spectroscopic observations
  31. GRB 241105a: PRIME near-infrared upper limits
  32. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  33. EP241107a: GIT optical observations
  34. EP241107a: SVOM/C-GFT optical observations
  35. EP241107a: AKO Optical Afterglow Detection
  36. GRB 241025A: LBT optical observations
  37. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  38. GRB 241105A: Swift/UVOT Detection
  39. EP241101a: CrAO ZTSH optical observations
  40. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  41. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  42. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  43. GRB 241105A: Swift-XRT afterglow detection
  44. GRB 241104A: Swift-XRT observations
  45. GRB 240511A: LCO upper limits
  46. GRB 241104A: Fermi GBM Observation
  47. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  48. GRB 241104A: NOT optical non-detection
  49. GRB 241104A: SVOM/VT optical candidate
  50. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  51. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  52. EP241104a: EP detection of GRB 241104A X-ray emission
  53. GRB 241010A: host galaxy redshift z = 0.977
  54. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  55. GRB 240821A: further radio observations with the VLA
  56. EP241101a: EP-FXT observations update
  57. EP241103a: GIT optical upper limit
  58. EP241021a: OHP/T193 further optical observations
  59. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  60. EP241103a: GOTO optical upper limit
  61. EP241103a: Swift XRT detection and improved X-ray position
  62. EP241021a: continued SOAR observations
  63. EP241101a: Optical upper limits with Kinder observations
  64. EP241101a: OHP/T193 optical observations
  65. EP241103a: Gemini optical limits
  66. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  67. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  68. EP241103A: LCO optical observations
  69. EP241103a: an X-ray transient detected by Einstein Probe
  70. GRB 241030A: Rapid release of TESS data.
  71. S241102cy: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  73. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  74. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  75. GRB241030A: OHP/T193 optical observations
  76. GRB 241101A: FRAM-ORM optical limit
  77. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  78. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  79. GRB 241030A: further SAO RAS optical observations
  80. GRB 241030A: Optical Observations via Virtual Telescope Project
  81. EP241021a: Liverpool Telescope optical follow-up observations
  82. GRB 241026A: SAO RAS optical observations
  83. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  84. GRB 241101A: Swift detection of a burst
  85. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  86. EP241021a: OHP/T193 optical observations
  87. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  88. GRB 241030B: Montarrenti Observatory optical upper limit
  89. EP241026b: Liverpool Telescope optical follow-up
  90. GRB 241030A: SAO RAS optical observations
  91. EP241021a: AMI-LA radio detection
  92. GRB 241030B : GIT optical upper limits
  93. GRB 241030B: LCOGT Optical Upper Limits
  94. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  95. GRB 241030B: Swift/UVOT Detection
  96. GRB 241029A: LCO optical detection
  97. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  98. GRB 241030B : MITSuME Akeno optical upper limits
  99. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  100. GRB 241030B: SVOM/VT optical afterglow observations

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