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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').
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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"

16161 results found.

  1. GRB 231117A: LDT Confirmation of Optical Fading
  2. GRB 231117A: Wendelstein Confirmation of Fading of the Optical Afterglow
  3. GRB 231117A : MITSuME Akeno optical afterglow candidate detection
  4. GRB 231118A: MeerLICHT afterglow detection
  5. GRB 231117A: OHP/T120 optical observations
  6. GRB 231118A: VLT/X-shooter redshift
  7. GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
  8. GRB 231117A: MAAO 0.7-m telescope optical upper limit
  9. GRB 231117A: AKO Follow-Up Observation
  10. GRB 231117A: 10 GHz VLA detection
  11. GRB 231118A: Las Cumbres optical detection
  12. GRB 231118A: LCOGT Optical Observations
  13. GRB 231118A: MASTER OT observation
  14. GRB 231118A: Continued Skynet Observations
  15. GRB 231118A: Skynet Optical Afterglow Discovery
  16. GRB 231117A: ePESSTO+ host galaxy redshift confirmation
  17. GRB 231117A: Keck spectroscopy of afterglow candidate
  18. GRB 231115A: Wendelstein Optical/Infrared Observations
  19. GRB 231115A: JinShan optical upper limits
  20. GRB 231117A: GIT optical follow-up
  21. GRB 231117A: LT observations consistent with fading
  22. GRB 231117A: Keck observations indicate presence of optical afterglow in z~0.3-0.5 galaxy
  23. GRB 231117A: REM optical and NIR early-time observations
  24. GRB 231117A: AKO Optical Upper Limit
  25. GRB 231117A: ATLAS non-detection of an optical counterpart
  26. GRB 231115A : OHP/T120 optical upper limit
  27. GRB 231115A: optical observations from INAF observatories
  28. GRB 231117A : MITSuME Akeno optical upper limits
  29. GRB 231117A: GOTO optical upper limits
  30. GRB231115A: Liverpool Telescope imaging
  31. GRB 231115A: NuSTAR Follow-Up Observations
  32. GRB 231115A: Swift-XRT and Swift-UVOT observations
  33. GRB 231115A : MITSuME Akeno and Okayama optical upper limits
  34. GRB 231115A: Gaoyazi/GOT follow-up and archival observations
  35. GRB 231115A: archival Chandra X-ray observations
  36. GRB 231115A: Kinder observations with Lulin observatory
  37. GRB 231115A: GOTO pre-burst limits of AT2023xvj
  38. GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
  39. GRB 231106A: TESS identification of candidate optical counterpart
  40. GRB 231115A: MASTER optical observations
  41. GRB 231115A: archival HST observations
  42. GRB 231115A: GROWTH-India discovery of a potential optical counterpart
  43. GRB 231111A: Xinglong-2.16m optical observations
  44. GRB 231111A: TNG tentative redshift
  45. GRB 231111A: Leavitt Observatory optical observations
  46. GRB231111A: Optical follow-up observations with Mephisto
  47. GRB 231111A: GMG observation upper limit
  48. GRB 231111A: Osservatorio Astronomico "Nastro Verde" optical observations with detection of an optical counterpart
  49. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  50. GRB 231111A: Mondy optical observations
  51. GRB 231110A: GOTO optical upper limits
  52. GRB 231110A: SAO RAS optical observations
  53. GRB231111A: YAHPT Observations
  54. GRB231111A: GIT confirmation of the optical afterglow
  55. GRB 231111A: MASTER OT earlier detection
  56. GRB 231111A: Nanshan/HMT optical observations
  57. GRB 231111A: Swift detection of a burst with an optical counterpart
  58. IceCube-231103A: No candidates from the Zwicky Transient Facility
  59. GRB 231104A: FRAM-ORM optical limit
  60. GRB 231104A: Wendelstein Optical/Infrared Observations
  61. GRB 231104A: 3.6m DOT optical upper limit
  62. GRB 231104A: NOT upper limit
  63. GRB 231104A: Swift/UVOT Upper Limits
  64. GRB231104A: LCOGT Optical Upper Limits
  65. GRB 231024A: AKO Optical Counterpart Candidate
  66. GRB 231024A: Fermi GBM Observation
  67. GRB 231024A: X-shooter spectroscopy of AT2023vuc/GOTO23baj reveals a young supernova with flash ionisation features
  68. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  69. GRB 231024A: GOTO optical counterpart candidate
  70. The photometry of the transient in Messier 31 field: GMG observation
  71. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  72. GRB 231017A: 1.3m DFOT Optical upper limit
  73. IceCube-231004A: Upper limits from Fermi-GBM Observations
  74. GRB 231017A: GOTO optical upper limits
  75. GRB 231017A: JinShan optical upper limit
  76. IC231004A: Classification of AT2023uqf/ZTF23abidzvf as a rapidly-evolving supernova with CSM interaction
  77. GRB 231017A: Las Cumbres optical upper limit
  78. GRB 231017A: LCOGT Optical Upper Limits
  79. GRB231017A: GROWTH-India upper limits on the optical afterglow
  80. (correction) Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field
  81. Discovery of an optical transient with strong flaring activity: a new blazar candidate in the Messier 31 field.
  82. GRB 230827B: 10.4m GTC spectroscopic redshift
  83. Correction to Fermi GBM Statement for Trigger 716527670/230916144
  84. GRB 230812B : optical observations from MISTRAL at Observatoire de Haute-Provence
  85. GRB 230918B: GOTO detection of a fast-rising transient in the GBM localisation region
  86. AT 2023sva: NOT observations of the ZTF candidate afterglow
  87. ZTF and SEDM Observations of the Candidate Optical Afterglow AT 2023sva
  88. GRB 230906A: optical counterpart
  89. GRB 230911A: Swift-XRT afterglow detection
  90. GRB 230911A: GOTO optical counterpart candidate
  91. GRB230911C: BOOTES-6/DPRT optical upper limit
  92. GRB230911C: LCOGT Optical Upper Limits
  93. GRB 230911C: Swift/UVOT Upper Limits
  94. GRB 230911C: GOTO optical upper limits
  95. GRB 230903A: TESS observations of optical emission
  96. GRB 230906A: Swift/UVOT Upper Limits
  97. GRB 230205A: LBT spectroscopy of two host galaxy candidates
  98. GRB 230903A: VLT/X-shooter optical observations
  99. GRB 230903A: LCOGT Optical Upper Limits
  100. GRB 230827B / GRB 230827256: Fermi GBM Observation

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