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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.

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

16181 results found.

  1. GRB 230728A: BOOTES-1 optical upper limit
  2. GRB 230728A: LCOGT Optical Upper Limit
  3. GRB 230728A: Swift/UVOT Upper Limits
  4. GRB 230728A: NOT optical observations and possible host galaxy
  5. GRB 230723B: Further CAHA observations and host galaxy detection
  6. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  7. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  8. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  9. GRB 230723B: Montarrenti Observatory upper limit
  10. GRB 230723B: Optical afterglow candidate from CAHA
  11. GRB 230723B: Bassano Bresciano Observatory upper limit
  12. GRB 230723B: Optical limit from CAHA
  13. GRB 230723B: Swift/UVOT Upper Limits
  14. LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
  15. GRB 230328B: LBT detection of the likely host galaxy
  16. LIGO/Virgo/KAGRA S230627c: observations of ZTF23aaptsuy/AT2023lx in AbAO observatory
  17. GRB 230628E: Swift/UVOT Detection
  18. AT2023lcr (ATLAS23msn/ZTF23aaoohpy): ALMA 100 GHz Detection
  19. GRB 230628E - VLT spectroscopic observations
  20. ZTF23aaoohpy/AT2023lcr: LBT observations
  21. GRB230628E: VLT optical identification of afterglow candidate
  22. GRB 230628E: LCOGT Optical Upper Limit
  23. LIGO/Virgo/KAGRA S230516az: GOTO candidate counterpart GOTO23hu ruled out by Zwicky Transient Facility observations
  24. ZTF23aaoohpy /AT2023lcr: TNG NIR detection
  25. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  26. ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
  27. ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
  28. MAXI GRB 230623A: MASTER optical observations
  29. ZTF23aaoohpy/AT2023lcr: SAO RAS observations
  30. AT2023lcr: VLA radio detection
  31. ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
  32. ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
  33. ZTF23aaoohpy/AT2023lc: Mondy optical observations
  34. AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
  35. ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
  36. ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
  37. ZTF23aaoohpy/AT2023lcr: Liverpool Telescope detection
  38. ZTF23aaoohpy/AT2023lcr: OHP/T193 and OHP/T120 optical follow-up observations
  39. ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
  40. GRB 230618A: Swift/UVOT Upper Limits
  41. GRB 230618A: KAIT Optical Observations
  42. GRB230618A: LCOGT Optical Observations
  43. LIGO/Virgo/KAGRA S230615az: T80S Search and Candidate Counterpart Identification
  44. LIGO/Virgo/KAGRA S230615az: Non-Detections of GROWTH-India Candidates from GECKO Optical Observations
  45. LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
  46. GRB 230606A: LCOGT Optical Observations
  47. ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
  48. ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
  49. GRB 230606A: Gaoyazi/GOT optical upper limit
  50. GRB 230606A: BOOTES-5/JGT optical upper limit
  51. GRB 230606A: Swift/UVOT Upper Limits
  52. LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
  53. LIGO/Virgo/KAGRA S230521k: MASTER new OT discovery
  54. LIGO/Virgo/KAGRA S230521k: Additional candidates from Zwicky Transient Facility
  55. LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
  56. LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
  57. LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
  58. LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
  59. Improved IPN triangulation of GRB 230512A
  60. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  61. GRB 230512A: Liverpool Telescope observations
  62. GRB 230512A: GIT non detection of afterglow candidate
  63. GRB 230512A: Kitab possible afterglow candidate
  64. GRB 230510A: OHP/T193 and OHP/T120 optical observations
  65. GRB 230512A: GIT optical follow-up ZTF candidates
  66. GRB 230510A: GIT optical upper limits
  67. GRB 230510A: LCOGT Optical Upper Limit
  68. GRB 230510A: Gaoyazi/GOT optical upper limit
  69. GRB 230510A: Nanshan/NEXT optical afterglow detection
  70. GRB 230506B: Swift/UVOT further analysis
  71. GRB 230506C: SAO RAS optical observations
  72. GRB 230307A: JWST second-epoch observations
  73. GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
  74. GRB 230506B: LCOGT Optical Upper Limits
  75. GRB 230506C: Swift/UVOT Upper Limits
  76. GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
  77. GRB 230506B: MASTER optical observations
  78. GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
  79. GRB 230420A: AROMA-N Optical Upper Limit
  80. GRB 230427A: NOT optical upper limit
  81. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  82. GRB 230427A: Gaoyazi/GOT optical upper limit
  83. GRB 230427A: Nanshan/HMT optical upper limit
  84. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  85. GRB 230427A: GIT optical upper limit
  86. GRB 230427A: Bassano Bresciano Observatory upper limit
  87. GRB 230427A: GMG upper limit
  88. GRB 230427A : OHP/T193 optical upper limit
  89. GRB 230427A: BOOTES-5/JGT afterglow detection
  90. GRB 230426A: MASTER OT J023135.16-792104.8 optical counterpart discovery
  91. GRB 230427A: MITSuME Akeno optical upper limits
  92. GRB 230427A: Swift detection of a burst with an optical counterpart
  93. GRB 230423A: Swift/UVOT Upper Limits
  94. GRB 230420A: Lowell Discovery Telescope Optical Detection
  95. GRB 230420A: Swift/UVOT Upper Limits
  96. GRB230420A: VLT optical observation
  97. GRB 230420A: MITSuME Akeno optical observation
  98. GRB 230420A: NOT optical afterglow confirmation
  99. GRB 230420A: Gaoyazi/GOT optical upper limit
  100. GRB 230420A: BOOTES-5/JGT optical afterglow detection

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