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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"

16146 results found.

  1. GRB240419A: Skynet Optical Afterglow Analysis
  2. GRB240418A - Candidate afterglow from NIRES
  3. GRB 240419B: Swift/UVOT Upper Limits
  4. GRB 240419A: Swift/UVOT Upper Limits
  5. GRB 240419B: optical afterglow from the NOT
  6. EP240414a: Near-IR observations with NIRES and WINTER
  7. EP240414A: Terskol Zeiss-2000 optical upper limit
  8. GRB 240418A: Swift/UVOT Upper Limits
  9. GRB 240419A: REM NIR afterglow detection
  10. GRB 240411B: Swift/UVOT Detection
  11. EP240417a: YAHPT Optical Upper Limits
  12. GRB 240419A: VLT/UVES redshift of z = 5.178
  13. GRB 240419A: VLT optical afterglow detection
  14. EP240416a: J-band observations with WINTER
  15. EP240414a: GMG observation
  16. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  17. GRB 240418A: NOT optical upper limits
  18. GRB 240411A: GOTO early optical upper limits
  19. LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
  20. EP240416A: Terskol Zeiss-2000 optical upper limit
  21. EP240416A: Khureltogoot optical upper limit
  22. EP240416a: BOOTES-2/TELMA Optical Upper Limit
  23. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  24. EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
  25. LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
  26. LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
  27. EP 240416a: Xinglong and NOT decaying optical counterpart
  28. EP240416A: MASTER optical observations
  29. EP240416a: Kinder optical counterpart candidate
  30. GRB 240414A: AbAO optical upprer limit
  31. GRB 240415A: Swift/UVOT Detection
  32. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  33. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  34. GRB 240415A: Earliest optical followup with the Kinder observations
  35. EP 240414a: BOOTES-4/MET Optical Upper Limits
  36. EP240414a: EP-FXT follow-up observation
  37. GRB 240415A: OHP/T193 optical observations
  38. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  39. GRB 240415A: SAO RAS optical observations
  40. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  41. GRB 240415A: Mondy optical transient detection
  42. GRB 240414A: Photometric observation from 2.2m CAHA
  43. GRB 240414A: Swift/UVOT Detection
  44. LXT 240402A/GRB 240402B: Swift follow-up observations
  45. GRB 240414A: Mondy optical observations
  46. GRB 240414A: AKO Optical Upper Limit
  47. EP 240414a: NOT optical counterpart confirmation
  48. GRB240414A : J-band upper limits from WINTER
  49. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  50. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  51. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  52. EP240413A: GOTO optical upper limits
  53. GRB 240414A: Skynet Optical Afterglow Observations
  54. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  55. GRB 240414A : MITSuME Akeno optical upper limits
  56. GRB 240414A : OHP/T193 redshift determination
  57. GRB 240414A : OHP/T193 optical counterpart detection
  58. EP240408a: GSP optical upper limit
  59. GRB 240411B: CrAO/ZTSh optical observations
  60. GRB 240411B: Kinder observations with Lulin observatory
  61. GRB 240411B: 1.3m DFOT Optical observations
  62. GRB 240411B: OHP/T193 optical observations
  63. GRB 240411B: LCO optical afterglow detection
  64. EP240408A: MASTER optical observations
  65. EP240408a: GROND detection of a candidate counterpart
  66. EP240408a: BOOTES-6/DPRT optical upper limit
  67. X-ray transient EP240315a: second epoch e-MERLIN radio observations
  68. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  69. X-ray transient LXT 240402A: WFST optical upper limits​
  70. GRB/FXT 240402B: Kinder optical counterpart candidate
  71. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  72. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  73. X-ray transient LXT240402A: AST3-3 optical upper limits
  74. LXT 240402A: MASTER optical observations with AGN in error-box
  75. GRB 240402B: GWAC-F50A optical upper limit
  76. X-ray transient EP240331a: Kinder optical upper limits
  77. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  78. EP240331A: MASTER optical observations
  79. Transient EP240315a: J-band observations of AT2024eju with WIRC
  80. X-ray transient EP20240331a: MeerLICHT optical upper limits
  81. X-ray transient EP240315a: continued ATCA monitoring
  82. X-ray transient EP240315a: e-MERLIN radio observations
  83. X-ray transient EP240315a: Ondrejov D50 optical limit
  84. Transient EPW20240219aa: REM optical/NIR further observations
  85. X-ray transient EP240315a: ATCA detection of radio counterpart
  86. X-ray transient EP240315a: GTC/HiPERCAM photometry
  87. X-ray transient EP240315a: MeerKAT radio detection
  88. X-ray transient EP240315a: GTC/OSIRIS spectroscopic redshift confirmation
  89. X-ray transient EP240315a: PRIME near infrared detection
  90. X-ray transient EP240315a: 3.6 m TNG NIR detection
  91. X-ray transient EP240315a/AT2024eju: TShAO (Zeiss-1000) observatory optical upper limit
  92. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow
  93. X-ray transient EP240315a: Kitab observatory optical upper limitns
  94. X-ray transient EP240315a: Montarrenti Observatory optical upper limit
  95. X-ray transient EP240315a: orphan FXT?
  96. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  97. X-ray transient EP240315a: GROND J-band detection
  98. X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
  99. X-ray transient EP240315a: Nanshan/HMT optical upper limit
  100. AT2024eju: followup observations with Liverpool Telescope suggest a fading transient

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