Properties

Label 2.61.a_dt
Base field $\F_{61}$
Dimension $2$
$p$-rank $2$
Ordinary yes
Supersingular no
Simple no
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:  $( 1 - 5 x + 61 x^{2} )( 1 + 5 x + 61 x^{2} )$
  $1 + 97 x^{2} + 3721 x^{4}$
Frobenius angles:  $\pm0.396286106500$, $\pm0.603713893500$
Angle rank:  $1$ (numerical)
Jacobians:  $164$
Cyclic group of points:    yes

This isogeny class is not 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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $3819$ $14584761$ $51520204224$ $191652875015625$ $713342909985174579$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $62$ $3916$ $226982$ $13841908$ $844596302$ $51520034086$ $3142742836022$ $191707360642468$ $11694146092834142$ $713342908307466556$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 164 curves (of which all are hyperelliptic):

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{61^{2}}$.

Endomorphism algebra over $\F_{61}$
The isogeny class factors as 1.61.af $\times$ 1.61.f and its endomorphism algebra is a direct product of the endomorphism algebras for each isotypic factor. The endomorphism algebra for each factor is:
Endomorphism algebra over $\overline{\F}_{61}$
The base change of $A$ to $\F_{61^{2}}$ is 1.3721.dt 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-219}) \)$)$

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_fr$2$(not in LMFDB)
2.61.k_fr$2$(not in LMFDB)
2.61.a_adt$4$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.61.ak_fr$2$(not in LMFDB)
2.61.k_fr$2$(not in LMFDB)
2.61.a_adt$4$(not in LMFDB)
2.61.af_abk$6$(not in LMFDB)
2.61.f_abk$6$(not in LMFDB)