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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

24612 results found.

  1. GRB 241030B: TESS detection of optical counterpart
  2. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  3. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  4. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  5. LIGO/Virgo/KAGRA S241109bn: Upper limits from EP-WXT observations
  6. Integral GRB241109.89: Global MASTER-Net observations report
  7. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  9. EP241107a: AbAO optical upper limit
  10. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  11. GRB 241108A: Further COLIBRÍ Upper Limits on the Optical Counterpart
  12. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  13. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  14. EP241109a: confirmation of a stellar flare by BOOTES-7
  15. GRB 241108A: Swift-XRT observations
  16. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  17. EP241107a: KAIT optical observations
  18. GRB 241030A: TESS observations
  19. GRB 241108A: COLIBRÍ Upper Limits on the Optical Counterpart
  20. EP241107a: Kinder optical follow-up observations
  21. GRB 241025A: radio detection with the VLA
  22. EP241107a: AKO Optical Afterglow Follow-Up Observations
  23. EP241107a: GSP detects optical counterpart
  24. GRB 241105A: SVOM/GRM observation
  25. EP241107a: OHP/T193 photometric and spectroscopic observations
  26. GRB 241105a: PRIME near-infrared upper limits
  27. GRB 241105A: ePESSTO+ NTT optical afterglow detection
  28. EP241107a: GIT optical observations
  29. EP241107a: SVOM/C-GFT optical observations
  30. EP241107a: AKO Optical Afterglow Detection
  31. GRB 241025A: LBT optical observations
  32. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  33. GRB 241105A: Swift/UVOT Detection
  34. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  35. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  36. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  37. GRB 241105A: Swift-XRT afterglow detection
  38. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  39. GRB 241104A: Swift-XRT observations
  40. GRB 240511A: LCO upper limits
  41. GRB 241104A: Fermi GBM Observation
  42. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  43. GRB 241104A: SVOM/VT optical candidate
  44. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  45. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  46. EP241104a: EP detection of GRB 241104A X-ray emission
  47. GRB 241010A: host galaxy redshift z = 0.977
  48. EP241101a NUTTelA-TAO / BSTI Measurements 2024-11-02
  49. GRB 240821A: further radio observations with the VLA
  50. EP241103a: GIT optical upper limit
  51. EP241021a: OHP/T193 further optical observations
  52. LIGO/Virgo/KAGRA S241102br: OHP/T193 optical observations
  53. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  54. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  55. EP241103a: Swift XRT detection and improved X-ray position
  56. EP241021a: continued SOAR observations
  57. EP241101a: Optical upper limits with Kinder observations
  58. EP241101a: OHP/T193 optical observations
  59. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  60. LIGO/Virgo/KAGRA S241102br: EP-WXT X-ray follow-up and flux limits
  61. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  62. EP241103a: GSP optical upper limit
  63. EP241103A: LCO optical observations
  64. EP241103a: an X-ray transient detected by Einstein Probe
  65. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  66. S241102cy: Identification of a GW compact binary merger candidate
  67. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  68. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  69. Kinder optical follow-up observations of EP241021a, EP241026b, and EP241030a/GRB241030A
  70. GRB241030A: OHP/T193 optical observations
  71. GRB 241101A: FRAM-ORM optical limit
  72. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  73. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  74. EP241021a: Upper limit from Konus-Wind observations
  75. GRB 241101A: Swift-BAT refined analysis
  76. GRB 241030A: further SAO RAS optical observations
  77. GRB 241030A: Optical Observations via Virtual Telescope Project
  78. EP241021a: Liverpool Telescope optical follow-up observations
  79. GRB 241030B: Swift-XRT refined Analysis
  80. GRB 241026A: SAO RAS optical observations
  81. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  82. GRB 241101A: Swift detection of a burst
  83. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  84. EP241021a: OHP/T193 optical observations
  85. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  86. GRB 241030B: Montarrenti Observatory optical upper limit
  87. EP241026b: Liverpool Telescope optical follow-up
  88. GRB 241030A: SAO RAS optical observations
  89. GRB 241030A: Fermi GBM Observation
  90. EP241021a: AMI-LA radio detection
  91. GRB 241030B : GIT optical upper limits
  92. GRB 241030B: LCOGT Optical Upper Limits
  93. GRB 241030B: Swift-BAT refined analysis
  94. GRB 241030A: Swift-BAT refined analysis
  95. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  96. GRB 241030B: Swift/UVOT Detection
  97. GRB 241029A: LCO optical detection
  98. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  99. GRB 241030B : MITSuME Akeno optical upper limits
  100. GRB 241030A: COLIBRI Continuing Detection of the Afterglow

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