Properties

Label 2.61.k_bn
Base field $\F_{61}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple yes
Geometrically simple no
Primitive yes
Principally polarizable yes
Contains a Jacobian yes

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Invariants

Base field:  $\F_{61}$
Dimension:  $2$
L-polynomial:  $1 + 10 x + 39 x^{2} + 610 x^{3} + 3721 x^{4}$
Frobenius angles:  $\pm0.387808728290$, $\pm0.945524605043$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\zeta_{12})\)
Galois group:  $C_2^2$
Jacobians:  $108$
Cyclic group of points:    yes

This isogeny class is simple but not geometrically simple, primitive, ordinary, and not supersingular. It is principally polarizable and contains a Jacobian.

Newton polygon

This isogeny class is ordinary.

$p$-rank:  $2$
Slopes:  $[0, 0, 1, 1]$

Point counts

Point counts of the abelian variety

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4381$ $13760721$ $51898307344$ $191611008196569$ $713326906077465901$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $72$ $3700$ $228642$ $13838884$ $844577352$ $51519904486$ $3142746341352$ $191707333719364$ $11694146106042762$ $713342910332792500$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 108 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{61^{3}}$.

Endomorphism algebra over $\F_{61}$
The endomorphism algebra of this simple isogeny class is \(\Q(\zeta_{12})\).
Endomorphism algebra over $\overline{\F}_{61}$
The base change of $A$ to $\F_{61^{3}}$ is 1.226981.bfy 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-1}) \)$)$

Base change

This is a primitive isogeny class.

Twists

Below are some of the twists of this isogeny class.

TwistExtension degreeCommon base change
2.61.ak_bn$2$(not in LMFDB)
2.61.au_io$3$(not in LMFDB)
2.61.am_df$4$(not in LMFDB)

Below is a list of all twists of this isogeny class.

TwistExtension degreeCommon base change
2.61.ak_bn$2$(not in LMFDB)
2.61.au_io$3$(not in LMFDB)
2.61.am_df$4$(not in LMFDB)
2.61.m_df$4$(not in LMFDB)
2.61.a_w$6$(not in LMFDB)
2.61.u_io$6$(not in LMFDB)
2.61.ay_kg$12$(not in LMFDB)
2.61.aw_ji$12$(not in LMFDB)
2.61.ac_c$12$(not in LMFDB)
2.61.a_aw$12$(not in LMFDB)
2.61.c_c$12$(not in LMFDB)
2.61.w_ji$12$(not in LMFDB)
2.61.y_kg$12$(not in LMFDB)
2.61.a_aeq$24$(not in LMFDB)
2.61.a_eq$24$(not in LMFDB)