Genus 2 curve 6845.a.6845.1

• Label: 6845.a.6845.1
• Conductor: $6845$
• Discriminant: $6845$
• Mordell-Weil group: \(\Z \oplus \Z\)
• Sato-Tate group: $\mathrm{SU}(2)\times\mathrm{SU}(2)$
• \(\End(J_{\overline{\Q}}) \otimes \R\): \(\R \times \R\)
• \(\End(J_{\overline{\Q}}) \otimes \Q\): \(\Q \times \Q\)
• \(\End(J) \otimes \Q\): \(\Q \times \Q\)
• \(\overline{\Q}\)-simple: no
• \(\mathrm{GL}_2\)-type: yes

Minimal equation

$y^2 + x^3y = x^5 - 7x^3 - 16x^2 - 15x - 5$

(, )

Invariants

Conductor:	\( N \)	\(=\)	\(6845\)	\(=\)	\( 5 \cdot 37^{2} \)
Discriminant:	\( \Delta \)	\(=\)	\(6845\)	\(=\)	\( 5 \cdot 37^{2} \)

Igusa-Clebsch invariants

\( I_2 \)	\(=\)	\(24\)	\(=\)	\( 2^{3} \cdot 3 \)
\( I_4 \)	\(=\)	\(852\)	\(=\)	\( 2^{2} \cdot 3 \cdot 71 \)
\( I_6 \)	\(=\)	\(-14064\)	\(=\)	\( - 2^{4} \cdot 3 \cdot 293 \)
\( I_{10} \)	\(=\)	\(-27380\)	\(=\)	\( - 2^{2} \cdot 5 \cdot 37^{2} \)

Automorphism group

\(\mathrm{Aut}(X)\)	\(\simeq\)	$C_2^2$
\(\mathrm{Aut}(X_{\overline{\Q}})\)	\(\simeq\)	$C_2^2$

Rational points

Known points
\((1 : 0 : 0)\)	\((1 : -1 : 0)\)	\((-1 : 0 : 1)\)	\((-1 : 1 : 1)\)	\((-2 : 3 : 1)\)	\((-2 : 5 : 1)\)
\((3 : -7 : 1)\)	\((-3 : 7 : 4)\)	\((3 : -20 : 1)\)	\((-3 : 20 : 4)\)

Number of rational Weierstrass points: \(0\)

This curve is locally solvable everywhere.

Mordell-Weil group of the Jacobian

Group structure: \(\Z \oplus \Z\)

Generator	$D_0$						Height	Order
\((-1 : 0 : 1) - (1 : -1 : 0)\)	\(z (x + z)\)	\(=\)	\(0,\)	\(y\)	\(=\)	\(0\)	\(0.220557\)	\(\infty\)
\(D_0 - (1 : -1 : 0) - (1 : 0 : 0)\)	\(x^2 + 3xz + 3z^2\)	\(=\)	\(0,\)	\(y\)	\(=\)	\(-3xz^2 - 4z^3\)	\(0.102222\)	\(\infty\)

2-torsion field: 6.2.438080.1

BSD invariants

Hasse-Weil conjecture:	verified
Analytic rank:	\(2\)
Mordell-Weil rank:	\(2\)
2-Selmer rank:	\(2\)
Regulator:	\( 0.022546 \)
Real period:	\( 14.66307 \)
Tamagawa product:	\( 1 \)
Torsion order:	\( 1 \)
Leading coefficient:	\( 0.330594 \)
Analytic order of Ш:	\( 1 \)   (rounded)
Order of Ш:	square

Local invariants

Prime	ord(\(N\))	ord(\(\Delta\))	Tamagawa	L-factor	Cluster picture
\(5\)	\(1\)	\(1\)	\(1\)	\(( 1 - T )( 1 + 2 T + 5 T^{2} )\)
\(37\)	\(2\)	\(2\)	\(1\)	\(( 1 - T )( 1 + T )\)

Galois representations

For primes $\ell \ge 5$ the Galois representation data has not been computed for this curve since it is not generic.

For primes $\ell \le 3$, the image of the mod-$\ell$ Galois representation is listed in the table below, whenever it is not all of $\GSp(4,\F_\ell)$.

Prime \(\ell\)	mod-\(\ell\) image	Is torsion prime?
\(2\)	2.15.2	no
\(3\)	3.90.1	no

Sato-Tate group

\(\mathrm{ST}\)	\(\simeq\)	$\mathrm{SU}(2)\times\mathrm{SU}(2)$
\(\mathrm{ST}^0\)	\(\simeq\)	\(\mathrm{SU}(2)\times\mathrm{SU}(2)\)

Decomposition of the Jacobian

Splits over \(\Q\)

Decomposes up to isogeny as the product of the non-isogenous elliptic curve isogeny classes:
  Elliptic curve isogeny class 37.a
  Elliptic curve isogeny class 185.b

Endomorphisms of the Jacobian

Of \(\GL_2\)-type over \(\Q\)

Endomorphism ring over \(\Q\):

\(\End (J_{})\)	\(\simeq\)	an order of index \(2\) in \(\Z \times \Z\)
\(\End (J_{}) \otimes \Q \)	\(\simeq\)	\(\Q\) \(\times\) \(\Q\)
\(\End (J_{}) \otimes \R\)	\(\simeq\)	\(\R \times \R\)

All \(\overline{\Q}\)-endomorphisms of the Jacobian are defined over \(\Q\).