Properties

Label 2.47.a_abs
Base field $\F_{47}$
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:  $\F_{47}$
Dimension:  $2$
L-polynomial:  $1 - 44 x^{2} + 2209 x^{4}$
Frobenius angles:  $\pm0.172472032564$, $\pm0.827527967436$
Angle rank:  $1$ (numerical)
Number field:  \(\Q(\sqrt{-2}, \sqrt{-69})\)
Galois group:  $C_2^2$
Jacobians:  $80$
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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $2166$ $4691556$ $10779421734$ $23835525322896$ $52599131938241286$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $48$ $2122$ $103824$ $4884646$ $229345008$ $10779628138$ $506623120464$ $23811293859838$ $1119130473102768$ $52599131640652522$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 80 curves (of which all are hyperelliptic):

  • $y^2=15 x^6+4 x^5+36 x^4+36 x^3+28 x^2+20 x+19$
  • $y^2=28 x^6+20 x^5+39 x^4+39 x^3+46 x^2+6 x+1$
  • $y^2=4 x^6+22 x^5+44 x^4+42 x^3+44 x^2+45 x+15$
  • $y^2=20 x^6+16 x^5+32 x^4+22 x^3+32 x^2+37 x+28$
  • $y^2=21 x^6+41 x^5+5 x^4+35 x^3+21 x^2+36 x+26$
  • $y^2=11 x^6+17 x^5+25 x^4+34 x^3+11 x^2+39 x+36$
  • $y^2=5 x^6+21 x^5+13 x^4+13 x^3+28 x+15$
  • $y^2=25 x^6+11 x^5+18 x^4+18 x^3+46 x+28$
  • $y^2=23 x^6+7 x^5+27 x^4+28 x^3+15 x^2+12 x+10$
  • $y^2=21 x^6+35 x^5+41 x^4+46 x^3+28 x^2+13 x+3$
  • $y^2=8 x^6+x^5+32 x^4+2 x^3+36 x^2+x+15$
  • $y^2=40 x^6+5 x^5+19 x^4+10 x^3+39 x^2+5 x+28$
  • $y^2=34 x^6+x^5+24 x^4+35 x^3+36 x^2+8 x+13$
  • $y^2=29 x^6+5 x^5+26 x^4+34 x^3+39 x^2+40 x+18$
  • $y^2=36 x^6+27 x^5+25 x^4+16 x^3+42 x^2+40 x+20$
  • $y^2=39 x^6+41 x^5+31 x^4+33 x^3+22 x^2+12 x+6$
  • $y^2=39 x^6+11 x^5+6 x^4+30 x^3+11 x^2+34 x+16$
  • $y^2=7 x^6+8 x^5+30 x^4+9 x^3+8 x^2+29 x+33$
  • $y^2=31 x^6+40 x^5+24 x^4+35 x^3+13 x^2+x+5$
  • $y^2=14 x^6+12 x^5+26 x^4+34 x^3+18 x^2+5 x+25$
  • and 60 more

Decomposition and endomorphism algebra

All geometric endomorphisms are defined over $\F_{47^{2}}$.

Endomorphism algebra over $\F_{47}$
The endomorphism algebra of this simple isogeny class is \(\Q(\sqrt{-2}, \sqrt{-69})\).
Endomorphism algebra over $\overline{\F}_{47}$
The base change of $A$ to $\F_{47^{2}}$ is 1.2209.abs 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-69}) \)$)$

Base change

This is a primitive isogeny class.

Twists

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

TwistExtension degreeCommon base change
2.47.a_bs$4$(not in LMFDB)
2.47.ak_by$8$(not in LMFDB)
2.47.k_by$8$(not in LMFDB)