Properties

Label 2.61.q_he
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:  $( 1 + 8 x + 61 x^{2} )^{2}$
  $1 + 16 x + 186 x^{2} + 976 x^{3} + 3721 x^{4}$
Frobenius angles:  $\pm0.671149895095$, $\pm0.671149895095$
Angle rank:  $1$ (numerical)
Jacobians:  $53$
Cyclic group of points:    no
Non-cyclic primes:   $2, 5, 7$

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

$r$ $1$ $2$ $3$ $4$ $5$
$A(\F_{q^r})$ $4900$ $14288400$ $51089560900$ $191820284006400$ $713385900573062500$

Point counts of the curve

$r$ $1$ $2$ $3$ $4$ $5$ $6$ $7$ $8$ $9$ $10$
$C(\F_{q^r})$ $78$ $3838$ $225078$ $13853998$ $844647198$ $51519469678$ $3142746968838$ $191707335120478$ $11694145663746798$ $713342913746066398$

Jacobians and polarizations

This isogeny class is principally polarizable and contains the Jacobians of 53 curves (of which all are hyperelliptic):

  • $y^2=39 x^6+4 x^5+48 x^4+60 x^3+48 x^2+4 x+39$
  • $y^2=8 x^6+29 x^4+29 x^2+8$
  • $y^2=43 x^6+39 x^5+12 x^4+33 x^3+59 x^2+39 x+37$
  • $y^2=49 x^6+32 x^5+48 x^4+12 x^3+18 x^2+22 x+25$
  • $y^2=14 x^6+23 x^5+41 x^4+49 x^3+52 x^2+53 x+36$
  • $y^2=55 x^6+27 x^5+5 x^4+17 x^3+34 x^2+37 x+49$
  • $y^2=26 x^6+43 x^5+20 x^4+13 x^3+34 x^2+59 x+51$
  • $y^2=45 x^6+5 x^5+44 x^4+17 x^3+44 x^2+5 x+45$
  • $y^2=54 x^6+2 x^5+18 x^4+9 x^3+18 x^2+2 x+54$
  • $y^2=50 x^6+30 x^5+38 x^4+5 x^3+x^2+28 x+34$
  • $y^2=2 x^6+32 x^3+18$
  • $y^2=15 x^6+57 x^5+23 x^4+4 x^3+23 x^2+57 x+15$
  • $y^2=2 x^6+2 x^3+40$
  • $y^2=16 x^6+22 x^5+40 x^4+19 x^3+11 x^2+46 x+33$
  • $y^2=30 x^6+12 x^5+35 x^4+32 x^3+35 x^2+12 x+30$
  • $y^2=29 x^6+5 x^5+28 x^4+32 x^3+28 x^2+5 x+29$
  • $y^2=35 x^6+32 x^5+23 x^4+2 x^3+23 x^2+32 x+35$
  • $y^2=23 x^6+39 x^5+21 x^4+26 x^3+3 x^2+46 x+22$
  • $y^2=36 x^6+38 x^5+54 x^4+15 x^3+58 x^2+30 x+53$
  • $y^2=55 x^6+46 x^4+46 x^2+55$
  • and 33 more

Decomposition and endomorphism algebra

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

Endomorphism algebra over $\F_{61}$
The isogeny class factors as 1.61.i 2 and its endomorphism algebra is $\mathrm{M}_{2}($\(\Q(\sqrt{-5}) \)$)$

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.aq_he$2$(not in LMFDB)
2.61.a_cg$2$(not in LMFDB)
2.61.ai_d$3$(not in LMFDB)

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

TwistExtension degreeCommon base change
2.61.aq_he$2$(not in LMFDB)
2.61.a_cg$2$(not in LMFDB)
2.61.ai_d$3$(not in LMFDB)
2.61.a_acg$4$(not in LMFDB)
2.61.i_d$6$(not in LMFDB)